Playback method and playback device

ABSTRACT

A playback method according to one aspect of the present disclosure is performed by a Blu-ray device connected to a display device. The playback method includes obtaining, from a recording medium, output control information of content recorded on the recording medium; obtaining, from the recording medium, a video signal of the content recorded on the recording medium; and (a) outputting the obtained video signal to the display device without converting image quality of the video signal, when the obtained output control information does not restrict output of content using a first copyright protection technology, and (b) converting the image quality of the obtained video signal and outputting the video signal to the display device, when the obtained output control information restricts output of content using the first copyright protection technology and output using the first copyright protection technology is performed according to a type of the display device.

BACKGROUND 1. Technical Field

The present disclosure relates to a playback method and a playbackdevice.

2. Description of the Related Art

Conventionally, an image signal processing device for improvingdisplayable luminance levels is disclosed (see, for example, PTL 1).

CITATION LIST Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2008-167418

SUMMARY

In one general aspect, the techniques disclosed here feature a playbackmethod performed by a playback device that plays content, the playbackmethod including: obtaining a type of a display device connected to theplayback device;

obtaining, from a recording medium, output control information of thecontent recorded on the recording medium; obtaining, from the recordingmedium, a video signal of the content recorded on the recording medium;and (a) outputting the obtained video signal to the display devicewithout converting image quality of the video signal, when the obtainedoutput control information does not restrict output of content using afirst copyright protection technology, and (b) converting the imagequality of the obtained video signal and outputting the video signal tothe display device, when the obtained output control informationrestricts output of content using the first copyright protectiontechnology and output using the first copyright protection technology isperformed according to the obtained type of the display device.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for describing video technology evolution;

FIG. 2 is a diagram for describing a relationship among video creation,delivery methods, and display devices for when new video representationis introduced into content;

FIG. 3 is a diagram for describing a relationship among a master,delivery methods, and display devices for when HDR is introduced;

FIG. 4A is a diagram for describing an SDR display process in an SDRTV;

FIG. 4B is a diagram for describing an SDR display process in an SDRTVwith a peak luminance of 300 nit;

FIG. 5 is a diagram for describing conversion from HDR to SDR;

FIG. 6A is a diagram for describing Case 1 in which an HDR disc storesonly an HDR signal that supports HDR;

FIG. 6B is a diagram for describing Case 2 in which an HDR disc storesan HDR signal that supports HDR and an SDR signal that supports SDR;

FIG. 7 is a diagram for describing a conversion process from HDR topseudo-HDR;

FIG. 8A is a diagram showing examples of EOTFs (Electro-Optical TransferFunctions) for HDR and SDR;

FIG. 8B is a diagram showing examples of inverse EOTFs for HDR and SDR;

FIG. 9 is an illustrative diagram of a method for determining a codevalue of a luminance signal stored in content, and a process ofrestoring a luminance value from a code value upon playback;

FIG. 10A is a diagram showing an example of a display process ofperforming HDR display by converting an HDR signal in an HDRTV;

FIG. 10B is a diagram showing an example of a display process ofperforming HDR display using an HDR-compatible playback device and anSDRTV;

FIG. 10C is a diagram showing an example of a display process ofperforming HDR display using an HDR-compatible playback device and anSDRTV which are connected to each other through a standard interface;

FIG. 11 is a block diagram showing configurations of a conversion deviceand a display device of an exemplary embodiment;

FIG. 12 is flowcharts showing a conversion method and a display methodwhich are performed by the conversion device and the display device ofthe exemplary embodiment;

FIG. 13A is a diagram for describing an example of first luminanceconversion;

FIG. 13B is a diagram for describing another example of the firstluminance conversion;

FIG. 14 is a diagram for describing second luminance conversion;

FIG. 15 is a flowchart showing a detailed process for display setting;

FIG. 16 is a diagram for describing third luminance conversion;

FIG. 17 is a diagram for describing a conversion process from HDR topseudo-HDR;

FIG. 18 is a diagram for describing multiplexed data stored on a dualdisc;

FIG. 19 is a flowchart showing playback operation for a dual disc;

FIG. 20 is a diagram showing types of BDs;

FIG. 21 is a diagram showing more details of the types of BDs;

FIG. 22 is a first diagram showing data capacity to be recorded on BDs;

FIG. 23 is a second diagram showing data capacity to be recorded on BDs;

FIG. 24 is a diagram showing examples of a combination of a video streamand a graphics stream recorded on discs including BDs and dual-streamdiscs;

FIG. 25 is a diagram showing other examples of a combination of a videostream and a graphics stream recorded on discs including BDs anddual-stream discs;

FIG. 26 is a diagram showing still other examples of a combination of avideo stream and a graphics stream recorded on discs including BDs anddual-stream discs;

FIG. 27 is a schematic diagram showing content of processes performed bya Blu-ray (registered trademark) device in a manner appropriate tovarious types of BDs and various types of display devices;

FIG. 28 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a BD having a 2K_SDR stream recorded onthe BD;

FIG. 29 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a BD having a 2K_HDR stream recorded onthe BD;

FIG. 30 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a BD having a 4K_SDR stream (a 4K_SDRvideo stream and a 2K_SDR graphics stream) recorded on the BD;

FIG. 31 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a BD having a 4K_HDR stream (a 4K_HDRvideo stream and a 2K_HDR graphics stream) recorded on the BD;

FIG. 32 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a dual-stream disc having a 2K_HDR streamand a 2K_SDR stream recorded on the disc;

FIG. 33 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a dual-stream disc having a 4K_HDR streamand a 4K_SDR stream recorded on the disc;

FIG. 34 is a diagram showing specific content of processes for a case inwhich the Blu-ray device plays a dual-stream disc having a 4K_HDR streamand a 2K_SDR stream recorded on the disc;

FIG. 35 is a diagram showing specific content of processes for a case inwhich a Blu-ray device having a pseudo-HDR conversion function plays aBD having a 2K_HDR stream recorded on the BD;

FIG. 36 is a diagram showing specific content of processes for a case inwhich the Blu-ray device having the pseudo-HDR conversion function playsa BD having a 4K_SDR stream (a 4K_SDR video stream and a 2K_SDR graphicsstream) recorded on the BD;

FIG. 37 is a diagram showing specific content of processes for a case inwhich the Blu-ray device having the pseudo-HDR conversion function playsa dual-stream disc having a 2K_HDR stream and a 2K_SDR stream recordedon the disc;

FIG. 38 is a diagram showing specific content of processes for a case inwhich the Blu-ray device having the pseudo-HDR conversion function playsa dual-stream disc having a 4K_HDR stream and a 2K_SDR stream recordedon the disc;

FIG. 39 is a diagram showing detailed configurations of graphicsstreams;

FIG. 40 is a diagram showing types of BDs;

FIG. 41A is a first diagram showing flows of video signals from varioustypes of BDs to various types of display devices;

FIG. 41B is a second diagram showing flows of video signals from varioustypes of BDs to various types of display devices;

FIG. 42 is a diagram for describing a summary of processes performed bya Blu-ray device;

FIG. 43 is a first diagram showing a relationship between conversionperformed by the Blu-ray device and a standard digital output flag;

FIG. 44 is a first diagram showing details of the standard digitaloutput flag;

FIG. 45 is a diagram showing table D1 specified in FIG. 44;

FIG. 46 is a diagram showing table D2 specified in FIG. 44;

FIG. 47 is a second diagram showing a relationship between conversionperformed by the Blu-ray device and the standard digital output flag;and

FIG. 48 is a second diagram showing details of the standard digitaloutput flag.

DESCRIPTION OF EMBODIMENTS

(Findings Forming a Basis of the Present Disclosure)

A playback method according to one aspect of the present disclosure is aplayback method performed by a playback device that plays content. Theplayback method includes obtaining a type of a display device connectedto the playback device; obtaining, from a recording medium, outputcontrol information of the content recorded on the recording medium;obtaining, from the recording medium, a video signal of the contentrecorded on the recording medium; and (a) outputting the obtained videosignal to the display device without converting image quality of thevideo signal, when the obtained output control information does notrestrict output of content using a first copyright protectiontechnology, and (b) converting the image quality of the obtained videosignal and outputting the video signal to the display device, when theobtained output control information restricts output of content usingthe first copyright protection technology and output using the firstcopyright protection technology is performed according to the obtainedtype of the display device.

According to this, even when a method for outputting a video signal isrestricted, since a video signal whose image quality has been convertedis output, video can be appropriately displayed on various types ofdisplay devices. Such a playback method is shown in, for example, FIGS.43 and 47.

In addition, for example, the recording medium may record a plurality ofvideo signals for playing same content, at least one of a resolution anda luminance range differing between the plurality of video signals, andin the obtaining of the video signal, one video signal may be selectedfrom among the plurality of video signals according to the obtained typeof the display device, and the selected video signal may be obtainedfrom the recording medium.

That is, appropriate video can be displayed on a display device byplayback methods such as those shown in FIGS. 32 to 34, 37, and 38.

In addition, for example, the obtained type of the display device may beone of: a first type indicating a display device whose resolution is afirst resolution and which supports a first luminance range; a secondtype indicating a display device whose resolution is a second resolutionand which supports the first luminance range; a third type indicating adisplay device whose resolution is the first resolution and whichsupports a second luminance range; and a fourth type indicating adisplay device whose resolution is the second resolution and whichsupports the second luminance range, the second resolution may have alarger number of pixels than that of the first resolution, and thesecond luminance range may include the first luminance range and have ahigher peak luminance than that of the first luminance range.

In addition, for example, the playback device may further include astorage unit that stores: a first table defining one or more copyrightprotection technologies included in the first copyright protectiontechnology; and a second table defining one or more copyright protectiontechnologies included in a second copyright protection technology, thesecond copyright protection technology being more enhanced than thefirst copyright protection technology. In the obtaining of the outputcontrol information, an output flag indicating rules about use of thefirst table and the second table may be obtained, and whether to use thefirst copyright protection technology or use the second copyrightprotection technology may be determined according to the obtained typeof the display device. In the outputting, when the obtained video signalis output to the display device using the first copyright protectiontechnology, the copyright protection technologies defined in the firsttable may be used, and when the obtained video signal is output to thedisplay device using the second copyright protection technology, thecopyright protection technologies defined in the second table may beused.

In addition, for example, the copyright protection technologies definedin the first table may include HDCP (High-bandwidth Digital ContentProtection) 1.4, and the copyright protection technologies defined inthe second table may include HDCP 2.2.

In addition, for example, the conversion may be conversion to reduce aluminance range of the video signal.

In addition, for example, the obtained video signal may be a videosignal with a second resolution having a larger number of pixels thanthat of a first resolution, or a video signal with a second luminancerange including a first luminance range and having a higher peakluminance than that of the first luminance range. In the outputting, (a)when the obtained output flag is a first flag indicating that output ofcontent using the first copyright protection technology is notrestricted, the obtained video signal may be output to the displaydevice without converting the image quality of the video signal, usingeither one of the first copyright protection technology and the secondcopyright protection technology determined according to the obtainedtype of the display device, (b) when the obtained output flag is asecond flag indicating that output of content using the first copyrightprotection technology is restricted, (i) the obtained video signal maybe converted to a video signal with the first resolution and the firstluminance range, and the converted video signal may be output to thedisplay device using the first copyright protection technologydetermined according to the obtained type of the display device, or (ii)the obtained video signal may be output to the display device using thesecond copyright protection technology determined according to theobtained type of the display device, and (c) when the obtained outputflag is a third flag indicating that output of content using the firstcopyright protection technology is not allowed, the obtained videosignal may be output to the display device using the second copyrightprotection technology.

Flags used for such a playback method are shown in FIG. 44.

In addition, for example, in the outputting, when the display devicedoes not support the second copyright protection technology, (a) whenthe obtained output flag is the first flag, the obtained video signalmay be output to the display device using the first copyright protectiontechnology, (b) when the obtained output flag is the second flag, theconversion may be performed on the obtained video signal to reduce theimage quality, and the video signal may be output to the display deviceusing the first copyright protection technology, and (c) when theobtained output flag is the third flag, output of the obtained videosignal may be inhibited.

In addition, for example, the obtained video signal may be a videosignal with a second resolution having a larger number of pixels thanthat of a first resolution, or a video signal with a second luminancerange including a first luminance range and having a higher peakluminance than that of the first luminance range. In the outputting, (a)when the obtained output flag is a first flag indicating that output ofcontent using the first copyright protection technology is notrestricted, the obtained video signal may be output to the displaydevice without converting the image quality of the video signal, usingeither one of the first copyright protection technology and the secondcopyright protection technology determined according to the obtainedtype of the display device, and (b) when the obtained output flag is asecond flag indicating that output of content using the first copyrightprotection technology is restricted, (i) the obtained video signal maybe converted to a video signal with the first resolution and the firstluminance range, and the converted video signal may be output to thedisplay device using the first copyright protection technologydetermined according to the obtained type of the display device, or (ii)the obtained video signal may be output to the display device using thesecond copyright protection technology determined according to theobtained type of the display device.

Flags used for such a playback method are shown in FIG. 48.

In addition, for example, in the outputting, when the display devicedoes not support the second copyright protection technology, (a) whenthe obtained output flag is the first flag, the obtained video signalmay be output to the display device using the first copyright protectiontechnology, and (b) when the obtained output flag is the second flag,the conversion may be performed on the obtained video signal to reducethe image quality, and the video signal may be output to the displaydevice using the first copyright protection technology.

In addition, for example, the recording medium may record: a first videosignal whose resolution is the first resolution and whose luminancerange is the first luminance range; and a second video signal whoseresolution is the first resolution and whose luminance range is thesecond luminance range, and when the obtained output control informationrestricts output of content using the first copyright protectiontechnology, (a) when the obtained type of the display device is thefirst type, in the obtaining of the video signal, the first video signalmay be selected and the selected first video signal may be obtained fromthe recording medium, and in the outputting, the obtained first videosignal may be output to the display device using the first copyrightprotection technology, (b) when the obtained type of the display deviceis the second type, in the obtaining of the video signal, the firstvideo signal may be selected and the selected first video signal may beobtained from the recording medium, and in the outputting, the obtainedfirst video signal may be converted to the second resolution, and theconverted first video signal may be output to the display device using asecond copyright protection technology, the second copyright protectiontechnology being more enhanced than the first copyright protectiontechnology, (c) when the obtained type of the display device is thethird type, in the obtaining of the video signal, the second videosignal may be selected and the selected second video signal may beobtained from the recording medium, and in the outputting, the obtainedsecond video signal may be output to the display device using the secondcopyright protection technology, and (d) when the obtained type of thedisplay device is the fourth type, in the obtaining of the video signal,the second video signal may be selected and the selected second videosignal may be obtained from the recording medium, and in the outputting,the obtained second video signal may be converted to the secondresolution, and the converted second video signal may be output to thedisplay device using the second copyright protection technology.

That is, appropriate video can be displayed on a display device by aplayback method such as that shown in FIG. 32.

In addition, for example, the recording medium may record: a first videosignal whose resolution is the second resolution and whose luminancerange is the first luminance range; and a second video signal whoseresolution is the second resolution and whose luminance range is thesecond luminance range, and when the obtained output control informationrestricts output of content using the first copyright protectiontechnology, (a) when the obtained type of the display device is thefirst type, in the obtaining of the video signal, the first video signalmay be selected and the selected first video signal may be obtained fromthe recording medium, and in the outputting, the obtained first videosignal may be converted to the first resolution, and the converted firstvideo signal may be output to the display device using the firstcopyright protection technology, (b) when the obtained type of thedisplay device is the second type, in the obtaining of the video signal,the first video signal may be selected and the selected first videosignal may be obtained from the recording medium, and in the outputting,the obtained first video signal may be output to the display deviceusing a second copyright protection technology, the second copyrightprotection technology being more enhanced than the first copyrightprotection technology, (c) when the obtained type of the display deviceis the third type, in the obtaining of the video signal, the secondvideo signal may be selected and the selected second video signal may beobtained from the recording medium, and in the outputting, the obtainedsecond video signal may be converted to the first resolution, and theconverted second video signal may be output to the display device usingthe second copyright protection technology, and (d) when the obtainedtype of the display device is the fourth type, in the obtaining of thevideo signal, the second video signal may be selected and the selectedsecond video signal may be obtained from the recording medium, and inthe outputting, the obtained second video signal may be output to thedisplay device using the second copyright protection technology.

That is, video can be appropriately displayed on a display device by aplayback method such as that shown in FIG. 33.

In addition, for example, the recording medium may record: a first videosignal whose resolution is the first resolution and whose luminancerange is the first luminance range; and a second video signal whoseresolution is the second resolution and whose luminance range is thesecond luminance range, and when the obtained output control informationrestricts output of content using the first copyright protectiontechnology, (a) when the obtained type of the display device is thefirst type, in the obtaining of the video signal, the first video signalmay be selected and the selected first video signal may be obtained fromthe recording medium, and in the outputting, the obtained first videosignal may be output to the display device using the first copyrightprotection technology, (b) when the obtained type of the display deviceis the second type, in the obtaining of the video signal, the firstvideo signal may be selected and the selected first video signal may beobtained from the recording medium, and in the outputting, the obtainedfirst video signal may be converted to the second resolution, and theconverted first video signal may be output to the display device using asecond copyright protection technology, the second copyright protectiontechnology being more enhanced than the first copyright protectiontechnology, (c) when the obtained type of the display device is thethird type, in the obtaining of the video signal, the second videosignal may be selected and the selected second video signal may beobtained from the recording medium, and in the outputting, the obtainedsecond video signal may be converted to the first resolution, and theconverted second video signal may be output to the display device usingthe second copyright protection technology, and (d) when the obtainedtype of the display device is the fourth type, in the obtaining of thevideo signal, the second video signal may be selected and the selectedsecond video signal may be obtained from the recording medium, and inthe outputting, the obtained second video signal may be output to thedisplay device using the second copyright protection technology.

That is, video can be appropriately displayed on a display device by aplayback method such as that shown in FIG. 34.

In addition, for example, the playback method may further includeobtaining a peak luminance of the display device connected to theplayback device, and when the obtained output control informationrestricts output of content using the first copyright protectiontechnology, (e) when the obtained type of the display device is thefirst type and the obtained peak luminance is higher than the firstluminance range, in the obtaining of the video signal, the second videosignal may be selected and the selected second video signal may beobtained from the recording medium, and in the outputting, the obtainedsecond video signal may be converted to a luminance range having theobtained peak luminance, and then further converted to the firstluminance range and converted to the first resolution, and the convertedsecond video signal may be output to the display device using the firstcopyright protection technology, and (f) when the obtained type of thedisplay device is the second type and the obtained peak luminance ishigher than the first luminance range, in the obtaining of the videosignal, the second video signal may be selected and the selected secondvideo signal may be obtained from the recording medium, and in theoutputting, the obtained second video signal may be converted to aluminance range having the obtained peak luminance, and then furtherconverted to the first luminance range, and the converted second videosignal may be output to the display device using the second copyrightprotection technology.

That is, video can be appropriately displayed on a display device by aplayback method including pseudo-HDR conversion, such as that shown inFIG. 37.

In addition, for example, the playback method may further includeobtaining a peak luminance of the display device connected to theplayback device, and when the obtained output control informationrestricts output of content using the first copyright protectiontechnology, (e) when the obtained type of the display device is thefirst type and the obtained peak luminance is higher than the firstluminance range, in the obtaining of the video signal, the second videosignal may be selected and the selected second video signal may beobtained from the recording medium, and in the outputting, the obtainedsecond video signal may be converted to a luminance range having theobtained peak luminance, and then further converted to the firstluminance range and converted to the first resolution, and the convertedsecond video signal may be output to the display device using the firstcopyright protection technology, and (f) when the obtained type of thedisplay device is the second type and the obtained peak luminance ishigher than the first luminance range, in the obtaining of the videosignal, the second video signal may be selected and the selected secondvideo signal may be obtained from the recording medium, and in theoutputting, the obtained second video signal may be converted to aluminance range having the obtained peak luminance, and then furtherconverted to the first luminance range, and the converted second videosignal may be output to the display device using the second copyrightprotection technology.

That is, video can be appropriately displayed on a display device by aplayback method including pseudo-HDR conversion, such as that shown inFIG. 38.

In addition, a playback device according to one aspect of the presentdisclosure is a playback device that plays content. The playback deviceincludes: a first obtainer that obtains a type of a display deviceconnected to the playback device; a second obtainer that obtains, from arecording medium, output control information of the content recorded onthe recording medium; a third obtainer that obtains, from the recordingmedium, a video signal of the content recorded on the recording medium;and an output unit that (a) outputs the obtained video signal to thedisplay device without converting image quality of the video signal,when the obtained output control information does not restrict output ofcontent using a first copyright protection technology, and (b) convertsthe image quality of the obtained video signal and outputs the videosignal to the display device, when the obtained output controlinformation restricts output of content using the first copyrightprotection technology and output using the first copyright protectiontechnology is performed according to the obtained type of the displaydevice.

In addition, for example, the playback device may further include astorage unit that stores: a first table defining one or more copyrightprotection technologies included in the first copyright protectiontechnology; and a second table defining one or more copyright protectiontechnologies included in a second copyright protection technology, thesecond copyright protection technology being more enhanced than thefirst copyright protection technology, and the second obtainer mayobtain an output flag indicating rules about use of the first table andthe second table, and determine whether to use the first copyrightprotection technology or use the second copyright protection technology,according to the obtained type of the display device, the obtained videosignal may be a video signal with a second resolution having a largernumber of pixels than that of a first resolution, or a video signal witha second luminance range including a first luminance range and having ahigher peak luminance than that of the first luminance range, and theoutput unit may: (a) output the obtained video signal to the displaydevice without converting the image quality of the video signal, usingeither one of the first copyright protection technology and the secondcopyright protection technology, when the obtained output flag is afirst flag indicating that output of content using the first copyrightprotection technology is not restricted; and (b) (i) convert theobtained video signal to a video signal with the first resolution andthe first luminance range, and output the converted video signal to thedisplay device using the first copyright protection technology, or (ii)output the obtained video signal to the display device using the secondcopyright protection technology, when the obtained output flag is asecond flag indicating that output of content using the first copyrightprotection technology is restricted.

Note that these comprehensive or specific aspects may be implemented bya system, a method, an integrated circuit, a computer program, or arecording medium such as a computer-readable CD-ROM, or may beimplemented by any combination of a system, a method, an integratedcircuit, a computer program, and a recording medium. A specific aspectof techniques of the present disclosure may be implemented as, forexample, a recording medium where the above-described rules (flag) arerecorded.

A playback method and a playback device according to one aspect of thepresent disclosure will be specifically described below with referenceto the accompanying drawings.

Note that each of exemplary embodiments which will be described belowshows one specific example of the present disclosure. Numerical values,shapes, materials, components, disposition positions and connectionmodes of the components, steps, order of the steps, and the like, whichare shown in the following exemplary embodiments are examples and thusare not intended to limit the present disclosure. In addition, of thecomponents of the following exemplary embodiments, components that arenot described in independent claims representing the broadest conceptare described as optional components.

First Exemplary Embodiment

[Findings Forming a Basis of a First Exemplary Embodiment]

The present inventors have found that the image signal processing devicedescribed in the “BACKGROUND ART” section has the following problem.

The image signal processing device disclosed in PTL 1 calculates, foreach pixel, a linear luminance based on linear RGB values calculatedfrom pixels forming a subject, calculates a corrected linear luminancefor each pixel and a corrected linear RGB value of combined pixels wherea plurality of pixels including the pixel are combined together, basedon the linear RGB values and the linear luminances, and calculates adisplay luminance and a display RGB value by performing gamma correctionon the corrected linear luminance and the corrected linear RGB value. Assuch, the image signal processing device achieves an increase in anumber of displayable gradations by correcting linear luminances basedon corrected linear RGB values.

However, luminance correction (conversion) by the image signalprocessing device disclosed in PTL 1, etc., does not cover a luminanceconversion method for correcting (converting) a luminance from a certainluminance range to a reduced luminance range.

The present disclosure relates to an image conversion/playback methodand device for displaying an HDR (High Dynamic Range) signal which is ahigh luminance signal having a high luminance range, on a display devicesuch as a TV, a projector, a tablet, or a smartphone that supports anSDR (Standard Dynamic Range) signal which is a normal luminance signalhaving a luminance range with a maximum luminance value of 100 nit.

[1-1. Background]

First, video technology transitions will be described with reference toFIG. 1. FIG. 1 is a diagram for describing video technology evolution.

For an achievement of a high image quality of video, primary attentionhas been focused on an increase in a number of display pixels so far,and video ranging from video with 720×480 pixels of Standard Definition(SD) to so-called 2K video with 1920×1080 pixels of High Definition (HD)has prevailed.

In recent years, with the aim of achieving a higher image quality ofvideo, introduction of so-called 4K video with 3840×1920 pixels of UltraHigh Definition (UHD) or with 4096×1920 pixels of 4K has started.

Then, it is considered to achieve a high image quality of video by, forexample, expanding dynamic range or color gamut or adding or improvingframe rate, together with an increase in video resolution by theintroduction of 4K.

Among them, for the dynamic range, attention is focused on HDR (HighDynamic Range) as a method that supports a luminance range whose maximumluminance value is increased to represent bright light at brightnesscloser to the real one, while dark part gradations of conventional videoare maintained. The bright light includes, for example, specularreflected light that cannot be represented by current TV signals.Specifically, a method for a luminance range supported by TV signalshaving been used so far is called SDR (Standard Dynamic Range), and hasa maximum luminance value of 100 nit; on the other hand, it is assumedthat a maximum luminance value of HDR is increased to 1000 nit or more.Standardization of HDR is in progress in SMPTE (Society of MotionPicture & Television Engineers), ITU-R (International TelecommunicationsUnion Radiocommunications Sector), etc.

For specific application of HDR, as with HD and UHD, it is assumed touse HDR in broadcasting, packaged media (Blu-ray (registered trademark)Discs, etc.), Internet delivery, etc.

Note that in the following, in video that supports HDR, luminances ofthe video have luminance values in an HDR luminance range, and aluminance signal obtained by quantizing the luminance values of thevideo is called an HDR signal. In video that supports SDR, luminances ofthe video have luminance values in an SDR luminance range, and aluminance signal obtained by quantizing the luminance values of thevideo is called an SDR signal.

[1-2. Relationship Among Master Creation, Delivery Methods, and DisplayDevices]

FIG. 2 is a diagram for describing a relationship among video creation,delivery methods, and display devices for when new video representationis introduced into content.

When new video representation (an increase in the number of pixels,etc.) is introduced to achieve a high image quality of video, as shownin FIG. 2, there is a need to (1) change a master for Home Entertainmentuse on a video creative side. Accordingly, there is also a need toupdate both (2) delivery methods such as broadcasting, communication,and packaged media, and (3) display devices such as a TV and a projectorthat display the video.

[1-3. Relationship Among a Master, Delivery Methods, and Display DevicesUpon Introduction of HDR]

In order for a user to enjoy content that supports new videorepresentation (e.g., high-luminance video content (HDR content)) athome, the user needs to newly adopt both an HDR-compatible deliverymethod and an HDR-compatible display device. That is, to enjoy contentthat supports new video representation at home, the user needs toprepare a delivery method and a display device that support the newvideo representation. This fact has been unavoidable also when new videorepresentation is introduced, such as when a transition is made from SDvideo to HD video, from HD video to 3D video, and from HD video to UHD(4K) video.

Hence, a change to new video representation depends on prevalence ofdisplay devices (e.g., TVs) having a new function. Such a changerequires new purchases of TVs, and replacement of TVs is not easy interms of high prices as well as size, weight, etc. Since both a mediumside and a content side cannot make large investments at the beginning,in many cases, prevalence of new video representation is delayed.

Thus, as shown in FIG. 3, for HDR, too, in order to fully make use oforiginal video representation of HDR, it is expected that there is aneed to newly purchase TVs (hereinafter, referred to as “HDRTVs”) thatsupport display of HDR-compatible video (hereinafter, referred to as“HDR display”).

[1-4. SDRTV]

To a TV (hereinafter, referred to as “SDRTV”) that supports only displayof SDR-compatible video (hereinafter, referred to as “SDR display”),normally, an input signal with luminance values of up to 100 nit isinput. Hence, if a display capability of the SDRTV is 100 nit, then itis sufficient for the SDRTV to represent the luminance values of theinput signal. However, in practice, many SDRTVs have a function ofplaying video with optimum luminance values according to a viewingenvironment (a dark room: cinema mode, and a bright room: dynamic mode,etc.), and thus are capable of representing video with 200 nit or more.That is, such SDRTVs can display video with up to a maximum luminance(e.g., 300 nit) of the display capability by selecting a display modedetermined according to the viewing environment.

However, for an input signal of an SDR method to be input to the SDRTV,an upper-limit luminance of the input signal is determined to be 100nit. Thus, it is difficult to use an SDRTV's high-luminance videoplayback capability which exceeds 100 nit, for playback of an HDRsignal, as long as an input interface of the SDR method is used as aconventional manner (see FIGS. 4A and 4B).

[1-5. HDR→SDR Conversion]

There is assumed a case in which high-luminance video content(hereinafter, also referred to as “HDR content” or “HDR video”)delivered by a delivery method, such as moving image delivery throughHDR-compatible broadcasting or communication network, or anHDR-compatible packaged medium (e.g., an HDR-compatible Blu-ray(registered trademark) Disc), is output by an SDRTV through anHDR-compatible playback device (e.g., a communication STB (Set Top Box),a Blu-ray (registered trademark) device, or an IPTV playback device). Ina case of playing the HDR content on the SDRTV, in order that the SDRTVcan properly display video, “HDR→SDR conversion” is implemented where anHDR signal that supports HDR is converted to an SDR signal with the SDRluminance range with a maximum value of 100 nit. By this, the SDRTV canperform, using the converted SDR signal, display of SDR video which isobtained by conversion from HDR video (see FIG. 5).

Note, however, that in this case, too, despite the fact that a user haspurchased HDR-compatible content (e.g., a Blu-ray (registered trademark)Disc or HDR IPTV content) and an HDR-compatible playback device (e.g., aBlu-ray (registered trademark) device or an HDR-compatible IPTV playbackdevice), the user can only enjoy video with SDR video representation(SDR representation) on the SDRTV. That is, even if the user preparesHDR content and a playback device that supports HDR, when the user doesnot have a display device that supports HDR (e.g., an HDRTV) but onlyhas an SDRTV, the user cannot view video with HDR video representation(HDR representation).

Thus, even if the user purchases HDR content and a transmission medium(playback device), unless the user prepares an HDRTV, the user does notunderstand a value of HDR (i.e., superiority of HDR over SDR by the factthat HDR has high image quality). As such, since the user does notunderstand the value of HDR unless the user has an HDRTV, it can be saidthat prevalence of HDR content and HDR-compatible delivery methods isdetermined according to HDRTV's prevalence speed.

[1-6. Two Methods that Implement HDR→SDR Conversion]

When an HDR signal is sent to a TV using a Blu-ray (registeredtrademark) Disc (BD), two cases can be assumed as shown in the followingFIGS. 6A and 6B. FIG. 6A is a diagram for describing Case 1 in which anHDR-compatible BD stores only an HDR signal that supports HDR. FIG. 6Bis a diagram for describing Case 2 in which an HDR-compatible BD storesan HDR signal that supports HDR and an SDR signal that supports SDR.

As shown in FIG. 6A, in Case 1, in a case of allowing an HDRTV todisplay video obtained by playing a BD on a Blu-ray (registeredtrademark) device, when an HDR-compatible BD (hereinafter, referred toas “HDRBD”) is played or when an SDR-compatible BD (hereinafter,referred to as “SDRBD”) is played, the Blu-ray (registered trademark)device outputs to the HDRTV a luminance signal stored on the BD as it iswithout converting the luminance signal. Then, since the HDRTV canperform a display process on both an HDR signal and an SDR signal, theHDRTV performs a display process according to the input luminancesignal, and thereby displays HDR video or SDR video.

On the other hand, in Case 1, in a case of allowing an SDRTV to displayvideo obtained by playing a BD on the Blu-ray (registered trademark)device, when the HDRBD is played, the Blu-ray (registered trademark)device performs a conversion process of converting an HDR signal to anSDR signal, and outputs the SDR signal obtained by the conversionprocess to the SDRTV. In addition, when the SDRBD is played, the Blu-ray(registered trademark) device outputs to the SDRTV an SDR signal storedon the BD as it is without converting the SDR signal. By this, the SDRTVdisplays SDR video.

In addition, as shown in FIG. 6B, in Case 2, a case of allowing an HDRTVto display video obtained by playing a BD on the Blu-ray (registeredtrademark) device is the same as Case 1.

On the other hand, in Case 2, in a case of allowing an SDRTV to displayvideo obtained by playing a BD on a Blu-ray (registered trademark)device, when an HDRBD is played or when an SDRBD is played, the Blu-ray(registered trademark) device outputs to the SDRTV an SDR signal storedon the BD as it is without converting the SDR signal.

In both Case 1 and Case 2, even when a user purchases HDRBD and aBlu-ray (registered trademark) device that supports HDR, if the userdoes not have an HDRTV, the user can only enjoy SDR video. Therefore, inorder for the user to view HDR video, an HDRTV is required and thusprevalence of HDR-compatible Blu-ray (registered trademark) devices orHDRBDs is expected to take time.

[1-7. HDR→Pseudo-HDR Conversion]

From the above fact, it can be said that to promote prevalence of HDR,it is important that commercialization of HDR content and deliverymethods can be promoted without waiting for prevalence of HDRTVs. To doso, if a user can be allowed to view an HDR signal on an existing SDRTV,as HDR video or pseudo-HDR video which is closer to HDR video than SDRvideo, instead of SDR video, then the user can view higher image qualityvideo which is close to HDR video and obviously different from SDRvideo, without purchasing an HDRTV. That is, if the user can viewpseudo-HDR video on the SDRTV, then it becomes possible for the user toview higher image quality video than SDR video, only by preparing HDRcontent and an HDR delivery device without preparing an HDRTV. In short,allowing the user to view pseudo-HDR video on the SDRTV may motivate auser to purchase HDR content and an HDR delivery device (see FIG. 7).

To implement display of pseudo-HDR video on the SDRTV, instead ofconverting an HDR signal to an SDR video signal, there is a need toimplement an “HDR→pseudo-HDR conversion process” so that the SDRTV canproperly display video of HDR content when the HDR content is played ina configuration in which the SDRTV is connected to an HDR deliverymethod. In the “HDR→pseudo-HDR conversion process”, a pseudo-HDR signalfor displaying video with a maximum luminance of an SDRTV's displaycapability, e.g., 200 nit or more, is generated using an input of avideo signal with a maximum value of 100 nit of the SDRTV, and thegenerated pseudo-HDR signal can be sent to the SDRTV.

[1-8. For EOTFs]

Now, EOTFs will be described with reference to FIGS. 8A and 8B.

FIG. 8A is a diagram showing examples of EOTFs (Electro-Optical TransferFunctions) for HDR and SDR.

An EOTF is generally called a gamma curve, and represents acorrespondence between a code value and a luminance value, and is toconvert a code value to a luminance value. That is, the EOTF isrelationship information indicating a correspondence relationshipbetween a plurality of code values and luminance values.

In addition, FIG. 8B is a diagram showing examples of inverse EOTFs forHDR and SDR.

An inverse EOTF represents a correspondence between a luminance valueand a code value, and is to convert a luminance value to a code value byquantizing the luminance value, which is the other way around from theEOTF. That is, the inverse EOTF is relationship information indicating acorrespondence relationship between luminance values and a plurality ofcode values. For example, in a case of representing luminance values ofvideo that supports HDR by 10-bit gradation code values, luminancevalues in an HDR luminance range of up to 10,000 nit are quantized andmapped to 1024 integer values ranging from 0 to 1023. That is, byperforming quantization based on the inverse EOTF, the luminance valuesin the luminance range of up to 10,000 nit (the luminance values ofvideo that supports HDR) are converted to an HDR signal having 10-bitcode values. An EOTF for HDR (hereinafter, referred to as “HDR EOTF”) oran inverse EOTF for HDR (hereinafter, referred to as “HDR inverse-EOTF”)can represent higher luminance values than an EOTF for SDR (hereinafter,referred to as “SDR EOTF”) or an inverse EOTF for SDR (hereinafter,referred to as “SDR inverse-EOTF”). For example, in FIGS. 8A and 8B, amaximum value of luminance (peak luminance) is 10,000 nit. That is, theHDR luminance range includes the whole SDR luminance range, and an HDRpeak luminance is higher than an SDR peak luminance. The HDR luminancerange is a luminance range where a maximum value is increased from 100nit which is a maximum value of the SDR luminance range, to 10,000 nit.

For example, an example of the HDR EOTF and the HDR inverse-EOTFincludes SMPTE 2084 standardized by the Society of Motion Picture andTelevision Engineers (SMPTE).

Note that in the following specification a luminance range from 0 nit to100 nit (peak luminance) which is described in FIGS. 8A and 8B may bedescribed as a first luminance range. Likewise, a luminance range from 0nit to 10,000 nit (peak luminance) which is described in FIGS. 8A and 8Bmay be described as a second luminance range.

[1-9. How to Use the EOTFs]

FIG. 9 is an illustrative diagram of a method for determining a codevalue of a luminance signal stored in content, and a process ofrestoring a luminance value from a code value upon playback.

A luminance signal representing luminances in the present example is anHDR signal that supports HDR. An image obtained after grading isquantized by the HDR inverse-EOTF, by which code values corresponding toluminance values of the image are determined. Image coding, etc., areperformed based on the code values, by which a video stream isgenerated. Upon playback, decoding results of the stream are inverselyquantized based on the HDR EOTF and are thereby converted to a linearsignal, and a luminance value for each pixel is restored. Quantizationusing the HDR inverse-EOTF is hereinafter referred to as “inverse HDREOTF conversion”. Inverse quantization using the HDR EOTF is referred toas “HDR EOTF conversion”. Likewise, quantization using the SDRinverse-EOTF is referred to as “inverse SDR EOTF conversion”. Inversequantization using the SDR EOTF is referred to as “SDR EOTF conversion”.

[1-10. Necessity of Pseudo-HDR]

Next, necessity of pseudo-HDR will be described with reference to FIGS.10A to 10C.

FIG. 10A is a diagram showing an example of a display process ofperforming HDR display by converting an HDR signal in an HDRTV.

As shown in FIG. 10A, in a case of displaying HDR video, even if adisplay device is an HDRTV, the display device may not be able todisplay a maximum value of the HDR luminance range (peak luminance (HPL(HDR Peak Luminance): e.g., 1500 nit)) as it is. In this case, luminanceconversion is performed to adjust a linear signal obtained afterperforming inverse quantization using the HDR EOTF, to a maximum valueof a luminance range of the display device (peak luminance (DPL (DisplayPeak Luminance): e.g., 750 nit)). Then, by inputting a video signalobtained by performing the luminance conversion to the display device,the display device can display HDR video that is adjusted to theluminance range with the maximum value which is the highest possiblevalue of the display device.

FIG. 10B is a diagram showing an example of a display process ofperforming HDR display using an HDR-compatible playback device and anSDRTV.

As shown in FIG. 10B, in a case of displaying HDR video with a displaydevice being an SDRTV, by using a fact that a maximum value of aluminance range (peak luminance (DPL: e.g., 300 nit)) of the SDRTV thatperforms display exceeds 100 nit, “HDR EOTF conversion” and “luminanceconversion” which are performed in an HDRTV are performed in an“HDR→pseudo-HDR conversion process” in the HDR-compatible playbackdevice (Blu-ray (registered trademark) device) in FIG. 10B. The“luminance conversion” uses the DPL (e.g., 300 nit) which is the maximumvalue of the luminance range of the SDRTV. If a signal obtained byperforming the “luminance conversion” can be directly input to a“display device” of the SDRTV, then even with the use of the SDRTV, thesame effect as that obtained by the HDRTV can be achieved.

However, since the SDRTV does not have any means for directly acceptingas input such a signal from an external source, the same effect cannotbe achieved.

FIG. 10C is a diagram showing an example of a display process ofperforming HDR display using an HDR-compatible playback device and anSDRTV which are connected to each other through a standard interface.

As shown in FIG. 10C, normally, there is a need to input such a signalthat can obtain the effect of FIG. 10B to the SDRTV, using an inputinterface (HDMI (registered trademark), etc.) included in the SDRTV. Onthe SDRTV, the signal having been input through the input interfacepasses through “SDR EOTF conversion”, “mode-by-mode luminanceconversion”, and a “display device” in this order, and video that isadjusted to a luminance range with a maximum value of the display deviceis displayed. Hence, an HDR-compatible Blu-ray (registered trademark)device generates such a signal (pseudo-HDR signal) that can cancel outthe “SDR EOTF conversion” and the “mode-by-mode luminance conversion”through which the signal passes immediately after the input interface onthe SDRTV. That is, in the HDR-compatible Blu-ray (registered trademark)device, “mode-by-mode inverse luminance conversion” and “inverse SDREOTF conversion” are performed immediately after “HDR EOTF conversion”and “luminance conversion” that uses a peak luminance (DPL) of theSDRTV. By this, the same effect as that achieved when a signal obtainedimmediately after the “luminance conversion” is input to the “displaydevice” (a dashed line arrow in FIG. 10C) is achieved in a pseudomanner.

[1-11. Conversion Device and Display Device]

FIG. 11 is a block diagram showing configurations of a conversion deviceand a display device of the exemplary embodiment. FIG. 12 is flowchartsshowing a conversion method and a display method which are performed bythe conversion device and the display device of the exemplaryembodiment.

As shown in FIG. 11, conversion device 100 includes HDR EOTF converter101, luminance converter 102, inverse luminance converter 103, andinverse SDR EOTF converter 104. In addition, display device 200 includesdisplay setting unit 201, SDR EOTF converter 202, luminance converter203, and display unit 204.

Detailed description of each component of conversion device 100 anddisplay device 200 will be made in description of a conversion methodand a display method.

[1-12. Conversion Method and Display Method]

A conversion method performed by conversion device 100 will be describedwith reference to FIG. 12. Note that the conversion method includessteps S101 to S104 which will be described below.

First, HDR EOTF converter 101 of conversion device 100 obtains HDR videohaving been subjected to inverse HDR EOTF conversion. HDR EOTF converter101 of conversion device 100 performs HDR EOTF conversion on an HDRsignal of the obtained HDR video (S101). By this, HDR EOTF converter 101converts the obtained HDR signal to a linear signal representingluminance values. An example of an HDR EOTF includes SMPTE 2084.

Then, luminance converter 102 of conversion device 100 performs firstluminance conversion of converting the linear signal converted by HDREOTF converter 101, using display characteristics information andcontent luminance information (S102). In the first luminance conversion,the luminance values set in the HDR luminance range (hereinafter,referred to as “HDR luminance values”) are converted to luminance valuesset in a display luminance range (hereinafter, referred to as “displayluminance values”). Details will be described later.

From the above-described fact, HDR EOTF converter 101 functions as anobtainer that obtains an HDR signal serving as a first luminance signalthat represents code values obtained by quantizing luminance values ofvideo. In addition, HDR EOTF converter 101 and luminance converter 102function as a converter that converts the code values represented by theHDR signal which is obtained by the obtainer, to display luminancevalues set in the display luminance range with a maximum value (DPL)which is smaller than a maximum value of the HDR luminance range (HPL)and larger than 100 nit. The display luminance range is determined basedon a luminance range of the display (display device 200).

More specifically, at step S101, for HDR code values serving as firstcode values represented by the obtained HDR signal, HDR EOTF converter101 determines HDR luminance values which are associated with the HDRcode values in the HDR EOTF, using the obtained HDR signal and the HDREOTF. Note that the HDR signal represents HDR code values obtained byquantizing luminance values of video (content), using an HDRinverse-EOTF where luminance values in the HDR luminance range areassociated with a plurality of HDR code values.

In addition, at step S102, luminance converter 102 performs firstluminance conversion of converting the HDR luminance values set in theHDR luminance range to display luminance values set in the displayluminance range, by determining, for the HDR luminance values determinedat step S101, display luminance values set in the display luminancerange which are associated in advance with the HDR luminance values.

In addition, prior to step S102, conversion device 100 obtains, asinformation about the HDR signal, content luminance informationincluding at least one of a maximum luminance value of the video(content) (CPL: Content Peak Luminance) and an average luminance valueof the video (CAL: Content Average Luminance). The CPL (first maximumluminance value) is, for example, a maximum value of luminance values ofa plurality of images forming HDR video. In addition, the CAL is, forexample, an average luminance value which is an average of the luminancevalues of the plurality of images forming the HDR video.

In addition, prior to step S102, conversion device 100 obtains displaycharacteristics information of display device 200 from display device200. Note that the display characteristics information is informationindicating display characteristics of display device 200, such as amaximum value of luminance (DPL) that can be displayed by display device200, a display mode of display device 200 (see description made later),and input and output characteristics (EOTF supported by the displaydevice).

In addition, conversion device 100 may transmit recommended displaysetting information (see description made later; hereinafter, alsoreferred to as “setting information”) to display device 200.

Then, inverse luminance converter 103 of conversion device 100 performsinverse luminance conversion determined according to the display mode ofdisplay device 200. By this, inverse luminance converter 103 performssecond luminance conversion of converting the luminance values set inthe display luminance range to luminance values set in the SDR luminancerange (0 to 100 [nit]) (S103). Details will be described later.Specifically, inverse luminance converter 103 performs second luminanceconversion of converting the display luminance values set in the displayluminance range to SDR luminance values set in the SDR luminance range,by determining, for the display luminance values obtained at step S102,SDR-compatible luminance values (hereinafter, referred to as “SDRluminance values”) serving as third luminance values set in the SDRluminance range with a maximum value of 100 nit, which are associated inadvance with the display luminance values.

Then, inverse SDR EOTF converter 104 of conversion device 100 performsinverse SDR EOTF conversion and thereby generates pseudo-HDR video(S104). Specifically, inverse SDR EOTF converter 104 quantizes thedetermined SDR luminance values, using an SDR (Standard Dynamic Range)inverse-EOTF (Electro-Optical Transfer Function) which is thirdrelationship information where the luminance values in the HDR luminancerange are associated with a plurality of third code values, determinesthird code values obtained by the quantization, and converts the SDRluminance values set in the SDR luminance range to an SDR signal servingas a third luminance signal that represents the third code values, andthereby generates a pseudo-HDR signal. Note that the third code valuesare SDR-compatible code values and are hereinafter referred to as “SDRcode values”. That is, the SDR signal is represented by SDR code valuesobtained by quantizing the luminance values of the video using the SDRinverse-EOTF where the luminance values in the SDR luminance range areassociated with a plurality of SDR code values. Then, conversion device100 outputs the pseudo-HDR signal (SDR signal) generated at step S104 todisplay device 200.

Conversion device 100 performs first luminance conversion and secondluminance conversion on HDR luminance values which are obtained byinversely quantizing an HDR signal, and thereby generates SDR luminancevalues that support pseudo-HDR. Then, conversion device 100 quantizesthe SDR luminance values using the SDR EOTF, and thereby generates anSDR signal that supports pseudo-HDR. Note that the SDR luminance valuesare numerical values in an SDR-compatible luminance range of 0 nit to100 nit, but since conversion based on the display luminance range hasbeen performed, the SDR luminance values are numerical values differentthan luminance values in the SDR-compatible luminance range of 0 nit to100 nit, which are obtained by performing luminance conversion on theHDR luminance values using the HDR EOTF and the SDR EOTF.

Next, a display method performed by display device 200 will be describedwith reference to FIG. 12. Note that the display method includes stepsS105 to S108 which will be described below.

First, display setting unit 201 of display device 200 sets displaysettings of display device 200, using setting information obtained fromconversion device 100 (S105). Here, display device 200 is an SDRTV. Thesetting information is information indicating display settings to berecommended to the display device 200, and is information indicating howpseudo-HDR video should be subjected to an EOTF and what settings thepseudo-HDR video should be displayed with, to display beautiful video(i.e., information for switching the display settings of display device200 to optimal display settings). The setting information includes, forexample, a gamma curve characteristic for output of the display device200, a display mode such as living mode (normal mode) or dynamic mode,and a numerical value of a backlight (brightness). In addition, amessage urging a user to change the display settings of display device200 by a manual operation may be displayed on display device 200(hereinafter, also referred to as “SDR display”). Details will bedescribed later.

Note that prior to step S105 display device 200 obtains an SDR signal(pseudo-HDR signal) and setting information indicating display settingsto be recommended to display device 200 for video display.

In addition, display device 200 only needs to obtain an SDR signal(pseudo-HDR signal) before step S106 and thus may obtain an SDR signal(pseudo-HDR signal) after step S105.

Then, SDR EOTF converter 202 of display device 200 performs SDR EOTFconversion on the obtained pseudo-HDR signal (S106). Specifically, SDREOTF converter 202 inversely quantizes the SDR signal (pseudo-HDRsignal) using an SDR EOTF. By this, SDR EOTF converter 202 converts SDRcode values represented by the SDR signal to SDR luminance values.

Then, luminance converter 203 of display device 200 performs luminanceconversion determined according to the display mode set on displaydevice 200. By this, luminance converter 203 performs third luminanceconversion of converting the SDR luminance values set in the SDRluminance range (0 to 100 [nit]) to display luminance values set in thedisplay luminance range (0 to DPL [nit]) (S107). Details will bedescribed later.

By the above-described processes, at steps S106 and S107, display device200 converts third code values represented by the obtained SDR signal(pseudo-HDR signal) to display luminance values set in the displayluminance range (0 to DPL [nit]), using the setting information obtainedat step S105.

More specifically, in conversion from the SDR signal (pseudo-HDR signal)to display luminance values, at step S106, for SDR code valuesrepresented by the obtained SDR signal, using an EOTF where theluminance values in the SDR luminance range are associated with aplurality of third code values, SDR luminance values associated with theSDR code values in the SDR EOTF are determined.

Then, in conversion to display luminance values, at step S107, thirdluminance conversion of converting the SDR luminance values set in theSDR luminance range to display luminance values set in the displayluminance range is performed by determining display luminance values setin the display luminance range which are associated in advance with thedetermined SDR luminance values.

Finally, display unit 204 of display device 200 displays pseudo-HDRvideo on display device 200 based on the converted display luminancevalues (S108).

[1-13. First Luminance Conversion]

Next, details of the first luminance conversion (HPL→DPL) at step S102will be described with reference to FIG. 13A. FIG. 13A is a diagram fordescribing an example of the first luminance conversion.

Luminance converter 102 of conversion device 100 performs firstluminance conversion of converting a linear signal (HDR luminancevalues) obtained at step S101, using display characteristics informationand content luminance information of HDR video. In the first luminanceconversion, the HDR luminance values (input luminance values) areconverted to display luminance values (output luminance values) that donot exceed a display peak luminance (DPL). The DPL is determined using amaximum luminance and a display mode of the SDR display which aredisplay characteristics information. The display mode is, for example,mode information such as cinema mode in which darker display isperformed on the SDR display, and dynamic mode in which brighter displayis performed. For example, when the maximum luminance of the SDR displayis 1,500 nit and the display mode sets such brightness that is 50% ofthe maximum luminance, the DPL is 750 nit. Here, the DPL (second maximumluminance value) is a maximum value of luminance that can be displayedby the SDR display in the currently set display mode. That is, in thefirst luminance conversion, the DPL serving as the second maximumluminance value is determined using the display characteristicsinformation which is information indicating display characteristics ofthe SDR display.

In addition, in the first luminance conversion, a CAL and a CPL includedin the content luminance information are used, and luminance valuessmaller than or equal to near the CAL are left unchanged before andafter the conversion, and only luminance values larger than or equal tonear the CPL are changed. Specifically, as shown in FIG. 13A, in thefirst luminance conversion, when a HDR luminance value is smaller thanor equal to the CAL, the HDR luminance value is not converted and isdetermined to be a display luminance value. When the HDR luminance valueis larger than or equal to the CPL, the DPL serving as the secondmaximum luminance value is determined to be a display luminance value.

In addition, in the first luminance conversion, a peak luminance of theHDR video (CPL) included in the content luminance information is used.When an HDR luminance value is the CPL, the DPL is determined to be adisplay luminance value.

Note that in the first luminance conversion, as shown in FIG. 13B, thelinear signal (HDR luminance values) obtained at step S101 may beconverted such that the HDR luminance values are clipped to values notexceeding the DPL. By performing such luminance conversion, processes ofconversion device 100 can be simplified, enabling to achieve downsizing,a reduction in power, and an increase in processing speed of the device.Note that FIG. 13B is a diagram for describing another example of thefirst luminance conversion.

[1-14. Second Luminance Conversion]

Next, details of the second luminance conversion (DPL→100 [nit]) at stepS103 will be described with reference to FIG. 14. FIG. 14 is a diagramfor describing the second luminance conversion.

Inverse luminance converter 103 of conversion device 100 performs,according to a display mode, inverse luminance conversion on the displayluminance values in the display luminance range (0 to DPL [nit]) whichare converted by the first luminance conversion at step S102. Theinverse luminance conversion is a process performed so that displayluminance values in the display luminance range (0 to DPL [nit])obtained after the process at step S102 can be obtained, when aluminance conversion process according to the display mode (step S107)by the SDR display is performed. That is, the second luminanceconversion is inverse luminance conversion of the third luminanceconversion.

By the above-described process, in the second luminance conversion, thedisplay luminance values (input luminance values) in the displayluminance range are converted to SDR luminance values (output luminancevalues) in the SDR luminance range.

In the second luminance conversion, a conversion formula is switchedaccording to the display mode of the SDR display. For example, when thedisplay mode of the SDR display is normal mode, luminances are convertedto directly proportional values which are directly proportional to thedisplay luminance values. In addition, in the second luminanceconversion, when the display mode of the SDR display is dynamic modethat makes high luminance pixels brighter than in normal mode and makeslow luminance pixels darker than in normal mode, by using an inversefunction, luminance conversion is performed such that an SDR luminancevalue of a low luminance pixel is converted to a higher value than adirectly proportional value which is directly proportional to a displayluminance value, and an SDR luminance value of a high luminance pixel isconverted to a lower value than a directly proportional value which isdirectly proportional to a display luminance value. That is, in thesecond luminance conversion, for the display luminance values determinedat step S102, luminance values associated with the display luminancevalues are determined to be SDR luminance values, using luminancerelationship information generated according to display characteristicsinformation which is information indicating the display characteristicsof the SDR display, and the luminance conversion process is switchedaccording to the display characteristics information. Here, theluminance relationship information generated according to displaycharacteristics information is, for example, information where displayluminance values (input luminance values) are associated with SDRluminance values (output luminance values). The luminance relationshipinformation is set for each display parameter (display mode) of the SDRdisplay, such as that shown in FIG. 14.

[1-15. Display Setting]

Next, details of display setting at step S105 will be described withreference to FIG. 15. FIG. 15 is a flowchart showing a detailed processfor display setting.

At step S105, display setting unit 201 of the SDR display performs thefollowing processes at steps S201 to S208.

First, display setting unit 201 determines, using setting information,whether an EOTF set on the SDR display (SDR display EOTF) matches anEOTF that is assumed upon generation of pseudo-HDR video (SDR signal)(S201).

If display setting unit 201 determines that the EOTF set on the SDRdisplay differs from the EOTF indicated by the setting information (EOTFthat matches the pseudo-HDR video) (Yes at S201), display setting unit201 determines whether the SDR display EOTF can be switched on a systemside (S202).

If display setting unit 201 determines that the SDR display EOTF can beswitched, display setting unit 201 switches the SDR display EOTF to anappropriate EOTF, using the setting information (S203).

From steps S201 to S203, in the setting of display settings (S105), theEOTF set on the SDR display is set to a recommended EOTF determinedaccording to the obtained setting information. In addition, by this, atstep S106 performed after step S105, SDR luminance values can bedetermined using the recommended EOTF.

If it is determined that the SDR display EOTF cannot be switched on thesystem side (No at S202), a message urging the user to change the EOTFby a manual operation is displayed on a screen (S204). For example, themessage “Set display gamma to 2.4” is displayed on a screen. That is, inthe setting of display settings (S105), when the EOTF set on the SDRdisplay cannot be switched, display setting unit 201 displays, on theSDR display, a message urging the user to switch the EOTF set on the SDRdisplay (SDR display EOTF) to a recommenced EOTF.

Then, the SDR display displays pseudo-HDR video (SDR signal), but beforethe display, it is determined, using the setting information, whether adisplay parameter of the SDR display matches the setting information(S205).

If display setting unit 201 determines that the display parameter set onthe SDR display differs from the setting information (Yes at S205),display setting unit 201 determines whether the display parameter of theSDR display can be switched (S206).

If display setting unit 201 determines that the display parameter of theSDR display can be switched (Yes at S206), display setting unit 201switches the display parameter of the SDR display, according to thesetting information (S207).

From steps S204 to S207, in the setting of display settings (S105), thedisplay parameter set on the SDR display is set to a recommended displayparameter determined according to the obtained setting information.

If it is determined that the display parameter of the SDR display cannotbe switched on the system side (No at S206), a message urging the userto change the display parameter set on the SDR display by a manualoperation is displayed on a screen (S208). For example, the message “Setthe display mode to dynamic mode and set the backlight to a maximumvalue” is displayed on a screen. That is, in the setting (S105), whenthe display parameter set on the SDR display cannot be switched, amessage urging the user to switch the display parameter set on the SDRdisplay to a recommended display parameter is displayed on the SDRdisplay.

[1-16. Third Luminance Conversion]

Next, details of the third luminance conversion (100→DPL [nit]) at stepS107 will be described with reference to FIG. 16. FIG. 16 is a diagramfor describing the third luminance conversion.

Luminance converter 203 of display device 200 converts the SDR luminancevalues in the SDR luminance range (0 to 100 [nit]) to the displayluminance value (0 to DPL [nit]), according to the display mode set atstep S105. This process is processed so as to be an inverse function ofthe mode-by-mode inverse luminance conversion at S103.

In the third luminance conversion, a conversion formula is switchedaccording to the display mode of the SDR display. For example, when thedisplay mode of the SDR display is normal mode (i.e., when the setdisplay parameter is a parameter corresponding to normal mode),luminance conversion is performed such that display luminance values areconverted to directly proportional values which are directlyproportional to the SDR luminance values. In addition, in the thirdluminance conversion, when the display mode of the SDR display isdynamic mode that makes high luminance pixels brighter than in normalmode and makes low luminance pixels darker than in normal mode,luminance conversion is performed such that a display luminance value ofa low luminance pixel is converted to a lower value than a directlyproportional value which is directly proportional to an SDR luminancevalue, and a display luminance value of a high luminance pixel isconverted to a higher value than a directly proportional value which isdirectly proportional to an SDR luminance value. That is, in the thirdluminance conversion, for the SDR luminance values determined at stepS106, using luminance relationship information generated according to adisplay parameter indicating a display setting of the SDR display,luminance values associated in advance with the SDR luminance values aredetermined to be display luminance values, and the luminance conversionprocess is switched according to the display parameter. Here, theluminance relationship information generated according to a displayparameter is, for example, information where SDR luminance values (inputluminance values) are associated with display luminance values (outputluminance values). The luminance relationship information is set foreach display parameter (display mode) of the SDR display, such as thatshown in FIG. 16.

[1-17. Effects, Etc.]

A normal SDRTV has an input signal with 100 nit, but is capable ofrepresenting video with 200 nit or more, according to a viewingenvironment (a dark room: cinema mode, and a bright room: dynamic mode,etc.). However, since an upper-limit luminance of the input signal tothe SDRTV is determined to be 100 nit, such a capability cannot bedirectly used.

In a case of displaying HDR video on the SDRTV, by using a fact that apeak luminance of the SDRTV that performs display exceeds 100 nit(normally, 200 nit or more), instead of converting the HDR video to SDRvideo with 100 nit or less, an “HDR→pseudo-HDR conversion process” isperformed such that gradations in a luminance range exceeding 100 nitare maintained to a certain degree. Hence, pseudo-HDR video close tooriginal HDR can be displayed on the SDRTV.

In a case in which this “HDR→pseudo-HDR conversion process” technique isapplied to Blu-ray (registered trademark), as shown in FIG. 17, when anHDR disc stores only an HDR signal and an SDRTV is connected to aBlu-ray (registered trademark) device, the Blu-ray (registeredtrademark) device performs an “HDR pseudo-HDR conversion process” andthereby converts the HDR signal to a pseudo-HDR signal, and sends thepseudo-HDR signal to the SDRTV. By this, the SDRTV converts the receivedpseudo-HDR signal to luminance values and can thereby display videohaving a pseudo-HDR effect. As such, even when there is noHDR-compatible TV, only by preparing an HDR-compatible BD and anHDR-compatible Blu-ray (registered trademark) device, even if a TV is anSDRTV, the SDRTV can display pseudo-HDR video having a higher imagequality than SDR video.

Therefore, although it has been considered that an HDR-compatible TV isrequired to view HDR video, a user can view pseudo-HDR video that allowsthe user to really feel an HDR-like effect, on an existing SDRTV. Bythis, prevalence of HDR-compatible Blu-ray (registered trademark) can beexpected.

An HDR signal sent through broadcasting, a packaged medium such asBlu-ray (registered trademark), or Internet delivery such as OTT isconverted to a pseudo-HDR signal by performing an HDR-to-pseudo-HDRconversion process. By this, the HDR signal can be displayed aspseudo-HDR video on an existing SDRTV.

Second Exemplary Embodiment

As described above, the first exemplary embodiment is described asexemplification of techniques disclosed in the present application.However, the techniques of the present disclosure are not limitedthereto, and are also applicable to the first exemplary embodiment wherechanges, replacements, additions, omissions, etc., are appropriatelymade. In addition, it is also possible to form a new exemplaryembodiment by combining together the components described in theabove-described first exemplary embodiment.

Hence, in the following, other exemplary embodiments are exemplified asa second exemplary embodiment.

HDR video is, for example, video contained in a Blu-ray (registeredtrademark) Disc, a DVD, an Internet moving image delivery site,broadcasting, or an HDD.

Conversion device 100 (HDR→pseudo-HDR conversion processor) may bepresent in a disc player, a disc recorder, a set-top box, a television,a personal computer, or a smartphone. Conversion device 100 may bepresent in a server device on the Internet.

Display device 200 (SDR display unit) is, for example, a television, apersonal computer, or a smartphone.

Display characteristics information obtained by conversion device 100may be obtained from display device 200 through an HDMI (registeredtrademark) cable or a LAN cable, using HDMI (registered trademark) orother communication protocols. For the display characteristicsinformation obtained by conversion device 100, display characteristicsinformation included in model information of display device 200, etc.,may be obtained through the Internet. Alternatively, a user may setdisplay characteristics information in conversion device 100 byperforming a manual operation. In addition, obtaining of displaycharacteristics information by conversion device 100 may be performedimmediately before generation of pseudo-HDR video (steps S101 to S104)or may be performed at timing when device's initial setting is performedor when a display is connected. For example, obtaining of displaycharacteristics information may be performed immediately beforeconversion to display luminance values, or may be performed at timingwhen conversion device 100 is connected to display device 200 for thefirst time by an HDMI (registered trademark) cable.

In addition, a CPL and a CAL of HDR video may be present for content ina one-to-one manner, or may be present for each scene. That is, in theconversion method, luminance information (CPL and CAL) may be obtainedthat is provided for each of a plurality of scenes of video and thatincludes, for each scene, at least one of a first maximum luminancevalue which is a maximum value of luminance values of a plurality ofimages forming the scene; and an average luminance value which is anaverage of the luminance values of the plurality of images forming thescene. In first luminance conversion, for each of the plurality ofscenes, display luminance values may be determined according toluminance information provided for the scene.

In addition, a CPL and a CAL may be included in the same medium (aBlu-ray (registered trademark) Disc, a DVD, etc.) as a medium includingHDR video, or may be obtained from a different location than that of theHDR video, e.g., a CPL and a CAL may be obtained by conversion device100 through the Internet. That is, luminance information including atleast one of a CPL and a CAL may be obtained as meta-information ofvideo, or may be obtained via a network.

In addition, in the first luminance conversion (HPL→DPL) of conversiondevice 100, fixed values may be used instead of using a CPL, a CAL, anda display peak luminance (DPL). In addition, the fixed values may bechangeable from an external source. In addition, the CPL, the CAL, andthe DPL may be switched among several types. For example, the DPL mayonly have three types: 200 nit, 400 nit, and 800 nit, or the closestvalue to display characteristics information may be used.

In addition, an HDR EOTF does not need to be SMPTE 2084 and other typesof HDR EOTF may be used. In addition, a maximum luminance of HDR video(HPL) does not need to be 10,000 nit and may be, for example, 4,000 nitor 1,000 nit.

In addition, a bit width of a code value may be, for example, 16, 14,12, 10, or 8 bits.

In addition, inverse SDR EOTF conversion is determined from displaycharacteristics information, but a fixed conversion function (which isalso changeable from an external source) may be used. The inverse SDREOTF conversion may use, for example, a function defined in Rec. ITU-RBT. 1886. Alternatively, types of inverse SDR EOTF conversion may benarrowed down to several types, and the closest type to input and outputcharacteristics of display device 200 may be selected and used.

In addition, for the display mode, a fixed mode may be used and thus thedisplay mode does not need to be included in display characteristicsinformation.

In addition, conversion device 100 does not need to transmit settinginformation, and display device 200 may have fixed display settings ordoes not need to change the display settings. In this case, displaysetting unit 201 is not required. In addition, the setting informationmay be flag information indicating whether video is pseudo-HDR video.For example, when video is pseudo-HDR video, settings may be changed toperform brightest display. That is, in the setting of display settings(S105), when obtained setting information indicates a signal indicatingpseudo-HDR video having been converted using a DPL, a brightness settingof display device 200 may be switched to a setting for performingbrightest display.

In addition, the first luminance conversion (HPL→DPL) of conversiondevice 100 is performed according to, for example, the followingformula.

$V = \left\{ \begin{matrix}L & {{{for}\mspace{14mu} 0}<=L < {S\; 1}} \\{{a*{\ln (L)}} + b} & {{{for}{\mspace{11mu} \;}S\; 1}<=L < {S\; 2}} \\M & {{{for}\mspace{14mu} S\; 2}<=L}\end{matrix} \right.$

Here, L represents a luminance value normalized to 0 to 1, and S1, S2,a, b, and M are values set based on a CAL, a CPL, and a DPL. In is anatural logarithm. V is a luminance value obtained after conversion andnormalized to 0 to 1. As shown in the example of FIG. 13A, when the CALis 300 nit, the CPL is 2,000 nit, the DPL is 750 nit, and conversion isnot performed up to CAL+50 nit but is performed for 350 nit or more,each value is, for example, as follows.

S1=350/10000

S2=2000/10000

M=750/10000

a=0.023

b=S1−a*ln(S1)=0.112105

That is, in the first luminance conversion, when an HDR luminance valueis between the average luminance value (CAL) and the first maximumluminance value (CPL), a display luminance value corresponding to theHDR luminance value is determined using the natural logarithm.

By converting HDR video using information such as a content peakluminance and a content average luminance of the HDR video, a conversionformula can be changed according to content, enabling to performconversion such that HDR gradations are maintained as much as possible.In addition, adverse effects such as too dark and too bright can besuppressed. Specifically, by mapping a content peak luminance of HDRvideo to a display peak luminance, gradations are maintained as much aspossible. In addition, by not changing pixel values smaller than orequal to near an average luminance, overall brightness remainsunchanged.

In addition, by converting HDR video using a peak luminance value and adisplay mode of an SDR display, a conversion formula can be changedaccording to a display environment of the SDR display, and video withHDR-ness (pseudo-HDR video) can be displayed at gradations andbrightness similar to those of the original HDR video, in accordancewith performance of the SDR display. Specifically, a display peakluminance is determined by a maximum luminance and a display mode of theSDR display, and HDR video is converted so as not to exceed the peakluminance value. By this, display is performed such that forbrightnesses displayable on the SDR display, gradations of the HDR videoare not reduced almost at all, and for undisplayable brightnesses,luminance values are reduced to displayable brightnesses.

By the above, undisplayable brightness information is trimmed anddisplayable brightness gradations are not lowered and thus video can bedisplayed in a form close to original HDR video. For example, for adisplay with a peak luminance of 1,000 nit, by converting video topseudo-HDR video whose peak luminance is suppressed to 1,000 nit,overall brightness is maintained, and luminance values change accordingto a display mode of the display. Hence, a luminance conversion formulais changed according to the display mode of the display. If a higherluminance than the peak luminance of the display is allowed forpseudo-HDR video, then the higher luminance may be replaced by the peakluminance on the display side and displayed. In that case, the overallvideo becomes darker than original HDR video. On the other hand, if alower luminance than the peak luminance of the display is converted as amaximum luminance, then the lower luminance is replaced by the peakluminance on the display side, and thus, the overall video becomesbrighter than the original HDR video. Moreover, the luminance is lowerthan the peak luminance on the display side, which means thatperformance of the display regarding gradations is not fully used.

In addition, on the display side, by switching display settings usingsetting information, pseudo-HDR video can be displayed more favorably.For example, when brightness is set to dark, high luminance displaycannot be performed, and thus, HDR-ness is impaired. In that case, bychanging the display settings or displaying a message urging to changethe display settings, performance of the display is fully exerted,enabling to display high gradation video.

In content on Blu-ray (registered trademark), etc., a video signal and agraphics signal such as subtitles or a menu are multiplexed together aspieces of independent data. Upon playback, the pieces of data aredecoded individually, and results of the decoding are combined togetherand displayed. Specifically, a subtitle or menu plane is superimposedonto a video plane.

Here, even if a video signal is HDR, a graphics signal such as subtitlesor a menu may be SDR. In HPL→DPL conversion of a video signal, thefollowing two ways of conversion (a) and (b) are possible.

(a) A case of performing HPL→DPL conversion after combining graphics

1. A graphics EOTF is converted from an SDR EOTF to an HDR EOTF.

2. Graphics obtained after the EOTF conversion are combined with video.

3. HPL→DPL conversion is performed on a result of the combining.

(b) A case of performing HPL→DPL conversion before combining graphics

1. A graphics EOTF is converted from an SDR EOTF to an HDR EOTF.

2. HPL→DPL conversion is performed on video.

3. Graphics obtained after the EOTF conversion and the video obtainedafter the DPL conversion are combined together.

Note that in the case of (b), steps 1 and 2 may be interchanged.

In both of the methods (a) and (b), a peak luminance of graphics is 100nit. However, when, for example, a DPL is a high luminance such as 1000nit, if the luminance of the graphics remains at 100 nit, then theluminance of the graphics may decrease with respect to video obtainedafter HPL→DPL conversion. Particularly, negative effects are assumed,such as darkening subtitles to be superimposed onto video. Therefore,for the graphics, too, luminance may be converted according to a DPLvalue. For example, for luminance of subtitles, a value of how muchpercent of the DPL value is to be set for the luminance of subtitles, orthe like, may be defined in advance, and the luminance of subtitles maybe converted based on the set value. Graphics other than subtitles suchas a menu can also be processed in the same manner.

The above describes playback operation for an HDR disc that stores onlyan HDR signal.

Next, multiplexed data stored on a dual disc on which both an HDR signaland an SDR signal are stored and which is shown in Case 2 in FIG. 6Bwill be described with reference to FIG. 18. FIG. 18 is a diagram fordescribing multiplexed data stored on a dual disc.

On the dual disc, as shown in FIG. 18, HDR signals and SDR signals arestored as different multiplexed streams. For example, on an optical discsuch as Blu-ray (registered trademark), pieces of data on a plurality ofmedia such as video, audio, subtitles, and graphics are stored as onemultiplexed stream by an MPEG-2 TS-based multiplexing method calledM2TS. These multiplexed streams are referred to by metadata for playbackcontrol, such as playlists. Upon playback, by a player analyzingmetadata, a multiplexed stream to be played or individual language datastored in a multiplexed stream is selected. The present example shows acase in which playlists for HDR and for SDR are stored individually, andeach playlist refers to HDR signals or SDR signals. In addition,identification information indicating that both HDR signals and SDRsignals are stored, etc., may be provided separately.

It is also possible to multiplex both HDR signals and SDR signals intothe same multiplexed stream. However, since multiplexing needs to beperformed so as to satisfy a buffer model such as T-STD (System TargetDecoder) defined in MPEG-2 TS, it is particularly difficult to multiplextwo pieces of video with a high bit rate within a range of predetermineddata read rates. Hence, it is desirable to demultiplex a multiplexedstream.

Data such as audio, subtitles, or graphics needs to be stored in eachmultiplexed stream and thus an amount of data increases compared to acase of multiplexing into one stream. Note, however, that for theincrease in the amount of data, an amount of video data can be reducedusing a video coding method with a high compression ratio. For example,by changing MPEG-4 AVC which is used for conventional Blu-ray(registered trademark) to HEVC (High Efficiency Video Coding), animprovement in compression ratio by a factor of 1.6 to 2 is expected. Inaddition, for content to be stored on a dual disc, only combinationsthat can fit to a capacity of an optical disc may be allowed, forexample, by allowing a combination of two 2Ks or 2K and 4K, such as acombination of 2K HDR and SDR or a combination of 4K SDR and 2K HDR, andby prohibiting storing of two 4Ks.

FIG. 19 is a flowchart showing playback operation for a dual disc.

First, a playback device determines whether an optical disc which is aplayback target is a dual disc (S301). Then, if it is determined thatthe disc is a dual disc (Yes at S301), it is determined whether a TVwhich is an output destination is an HDRTV or an SDRTV (S302). If it isdetermined that the TV is an HDRTV (Yes at S302), processing proceeds tostep S303. If it is determined that the TV is an SDRTV (No at S302),processing proceeds to step S304. At step S303, an HDR video signal isobtained from a multiplexed stream including HDR signals on the dualdisc, and decoded, and then output to the HDRTV. At step S304, an SDRvideo signal is obtained from a multiplexed stream including SDR signalson the dual disc, and decoded, and then output to the SDRTV. Note thatif it is determined, at step S301, that the playback target is not adual disc (No at S301), a determination as to whether playback can beperformed is made by a predetermined method, and a playback method isdetermined based on a result of the determination (S305).

In the conversion method of the present disclosure, in a case ofdisplaying HDR video on an SDRTV, by using a fact that a peak luminanceof the SDRTV that performs display exceeds 100 nit (normally, 200 nit ormore), instead of converting the HDR video to SDR video with 100 nit orless, an “HDR→pseudo-HDR conversion process” is implemented in whichconversion is performed such that gradations in regions exceeding 100nit are maintained to a certain degree, by which the HDR video isconverted to pseudo-HDR video close to original HDR, enabling to displaythe pseudo-HDR video on the SDRTV.

In addition, in the conversion method, a conversion method for the “HDRpseudo-HDR conversion process” may be switched according to displaycharacteristics (a maximum luminance, input and output characteristics,and a display mode) of the SDRTV.

For a method for obtaining display characteristics information, thefollowing methods are considered: (1) display characteristicsinformation is automatically obtained through HDMI (registeredtrademark) or a network; (2) display characteristics information isgenerated by allowing a user to input information such as amanufacturer's name and a product number; and (3) displaycharacteristics information is obtained from a cloud, etc., usinginformation such as a manufacturer's name and a product number.

In addition, for timing of obtaining display characteristics informationby conversion device 100, the following timing is considered: (1)display characteristics information is obtained immediately beforeperforming pseudo-HDR conversion; and (2) display characteristicsinformation is obtained when conversion device 100 is connected todisplay device 200 (SDRTV, etc.) for the first time (when a connectionis established).

In addition, in the conversion method, the conversion method may beswitched according to luminance information (a CAL and a CPL) of HDRvideo.

For example, for a method for obtaining luminance information of HDRvideo by conversion device 100, for example, the following methods areconsidered: (1) luminance information is obtained as meta-informationassociated with HDR video; (2) luminance information is obtained byallowing a user to input title information of content; and (3) luminanceinformation is obtained from a cloud, etc., using input informationhaving been input by the user.

In addition, for details of the conversion method, (1) conversion isperformed so as not to exceed a DPL, (2) conversion is performed suchthat a CPL becomes the DPL, (3) luminances lower than or equal to a CALand a neighborhood of the CAL are not changed, (4) conversion isperformed using a natural logarithm, and (5) a clipping process isperformed at the DPL.

In addition, in the conversion method, in order to enhance thepseudo-HDR effect, it is also possible to transmit display settings ofan SDRTV, such as a display mode and a display parameter, to displaydevice 200 to switch the display settings. For example, a message urginga user to perform display setting may be displayed on a screen.

Third Exemplary Embodiment

[3-1. Types of Discs]

A third exemplary embodiment will be described below. As describedabove, with an achievement of a high resolution and a high luminancerange of display devices, there are provided a plurality of types ofBlu-ray Discs (hereinafter, described as BDs) that match specificationsof the display devices. FIG. 20 is a diagram showing types of BDs. FIG.21 is a diagram showing more details of the types of BDs. A playbackdevice (Blu-ray device) plays content recorded on a BD which is insertedinto the playback device, and displays the content on a display device.As shown in FIGS. 20 and 21, in the following third exemplaryembodiment, a BD on which is recorded a video signal whose resolution isa first resolution and whose luminance range is a first luminance rangeis described as a 2K_SDR-compatible BD ((a) of FIG. 21). The videosignal whose resolution is the first resolution and whose luminancerange is the first luminance range is stored as a stream on the BD. Thestream is described as a 2K_SDR stream. The 2K_SDR-compatible BD is aconventional BD.

In addition, a BD on which is recorded a video signal whose resolutionis a second resolution and whose luminance range is the first luminancerange is described as a 4K_SDR-compatible BD. The video signal whoseresolution is the second resolution and whose luminance range is thefirst luminance range is stored as a stream on the BD. The stream isdescribed as a 4K_SDR stream ((b) of FIG. 21).

Likewise, a BD on which is recorded a video signal whose resolution isthe first resolution and whose luminance range is a second luminancerange is described as a 2K_HDR-compatible BD. The video signal whoseresolution is the first resolution and whose luminance range is thesecond luminance range is stored as a stream on the BD. The stream isdescribed as a 2K_HDR stream ((d) of FIG. 21).

In addition, a BD on which is recorded a video signal whose resolutionis the second resolution and whose luminance range is the secondluminance range is described as a 4K_HDR-compatible BD. The video signalwhose resolution is the second resolution and whose luminance range isthe second luminance range is stored as a stream on the BD. The streamis described as a 4K_HDR stream ((e) of FIG. 21).

Note that the first resolution is, for example, so-called 2K (1920×1080or 2048×1080) resolution, but may be any resolution including suchresolution. In the third exemplary embodiment, the first resolution maybe simply described as 2K.

In addition, the second resolution is so-called 4K (3840×2160 or4096×2160) resolution, but may be any resolution including suchresolution. The second resolution is a resolution having a larger numberof pixels than that of the first resolution.

Note that the first luminance range is, for example, SDR (a luminancerange with a peak luminance of 100 nit) having been described so far.The second luminance range is, for example, HDR (a luminance range witha peak luminance exceeding 100 nit) having been described so far. Thesecond luminance range includes the whole first luminance range, and thepeak luminance of the second luminance range is higher than the peakluminance of the first luminance range.

As shown in (c), (f), (g), and (h) of FIG. 21, a dual-stream disc thatsupports a plurality of video representations with a single BD isconsidered. The dual-stream disc is a BD on which are recorded aplurality of video signals for playing the same content. At least one ofthe resolution and the luminance range differs between the plurality ofvideo signals.

Specifically, a dual-stream disc shown in (c) of FIG. 21 is a BD onwhich are recorded a 4K_SDR stream and a 2K_SDR stream. A dual-streamdisc shown in (f) of FIG. 21 is a BD on which are recorded a 2K_HDRstream and a 2K_SDR stream.

A dual-stream disc shown in (g) of FIG. 21 is a BD on which are recordeda 4K_HDR stream and a 4K_SDR stream. A dual-stream disc shown in (h) ofFIG. 21 is a BD on which are recorded a 4K_HDR stream and a 2K_SDRstream.

Note that the dual-stream disc shown in (c) of FIG. 21 is not necessarybecause the Blu-ray device can perform down-conversion (hereinafter,also described as down-convert) of resolution from 4K to 2K.

[3-2. Disc Capacity]

Now, supplemental remarks on each BD such as those described above willbe made with reference to FIGS. 22 and 23. FIGS. 22 and 23 are diagramsshowing data capacity to be recorded on BDs.

FIGS. 22 and 23 exemplify stream data capacity to be actually used oneach BD and dual-stream disc.

FIG. 22 exemplifies cases in which streams with 2K resolution (a 2K_SDRstream and a 2K_HDR stream) are compressed using MPEG-4 AVC. Bit ratesof movie length, lossless audio, and compressed audio are as shownbelow. Note that a BD records a number of audio streams (lossless audioand compressed audio) that corresponds to a number of languages.

Movie length: 150 min (14 mbps to 18 mbps)

Lossless audio: 0 to 2 languages (4.5 mbps)

Compressed audio: 3 to 5 languages (1.5 mbps)

In this case, a maximum value (A), an intermediate value (B), and aminimum value (C) of required disc capacity are as follows.

(18+4.5*2+1.5*5) mbps*(150*60) s/8=38.8 GB  (A)

(16+4.5*1+1.5*3) mbps*(150*60) s/8=28.1 GB  (B)

(14+4.5*0+1.5*3) mbps*(150*60) s/8=20.8 GB  (C)

In addition, cases are exemplified in which streams with 4K resolution(a 4K_SDR stream and a 4K_HDR stream) are compressed using HEVC. Bitrates of movie length, lossless audio, and compressed audio are as shownbelow.

Movie length: 150 min (35 mbps to 40 mbps)

Lossless audio: 0 to 2 languages (4.5 mbps)

Compressed audio: 3 to 6 languages (1.5 mbps)

In this case, a maximum value (a), an intermediate value (b), and aminimum value (c) of required disc capacity are as follows.

(40+4.5*2+1.5*5) mbps*(150*60) s/8=63.6 GB  (a)

(37+4.5*0+1.5*4) mbps*(150*60) s/8=48.4 GB  (b)

(35+4.5*0+1.5*3) mbps*(150*60) s/8=44.4 GB  (c)

Here, disc capacity required for a dual-stream disc on which arerecorded both a 2K_HDR stream compressed using MPEG-4 AVC and a 2K_SDRstream compressed using MPEG-4 AVC is determined by the above-described(A)+(A), (B)+(B), and (C)+(C). Specifically, the maximum value is 77.6GB, the intermediate value is 56.2 GB, and the minimum value is 41. 6GB.

In addition to conventional 50 GB, a 66 GB disc and a 100 GB disc aretargeted, and thus, a dual-stream disc such as that described above isalso implementable in terms of capacity.

Note that disc capacity required for a dual-stream disc on which arerecorded both a 4K_HDR stream compressed using HEVC and a 4K_HDR streamcompressed using HEVC is 96.8 GB based on the above-described (b)+(b),and 88.8 GB based on the above-described (c)+(c). Hence, such adual-stream disc is implementable by a disc with 100 GB capacity.

Likewise, disc capacity required for a dual-stream disc on which arerecorded both a 4K_HDR stream compressed using HEVC and a 2K_SDR streamcompressed using MPEG-4 AVC is 91.7 GB based on the above-described(a)+(B), and 65.2 GB based on the above-described (c)+(C). Hence, such adual-stream disc is implementable by a disc with 100 GB capacity or adisc with 66 GB capacity.

Other examples will be further described with reference to FIG. 23. FIG.23 exemplifies cases in which streams with 2K resolution (a 2K_SDRstream and a 2K_HDR stream) are compressed using HEVC. Bit rates ofmovie length, lossless audio, and compressed audio are as shown below.

Movie length: 150 min (7 mbps to 9 mbps)

Lossless audio: 0 to 2 languages (4.5 mbps)

Compressed audio: 3 to 5 languages (1.5 mbps)

In this case, a maximum value (A), an intermediate value (B), and aminimum value (C) of required disc capacity are as follows.

(9+4.5*2+1.5*5) mbps*(150*60) s/8=25.3 GB  (α)

(8+4.5*1+1.5*3) mbps*(150*60) s/8=19.1 GB  (β)

(7+4.5*0+1.5*3) mbps*(150*60) s/8=12.9 GB  (γ)

Here, disc capacity required for a dual-stream disc on which arerecorded both a 2K_HDR stream compressed using HEVC and a 2K_SDR streamcompressed using HEVC is determined by the above-described (α)+(α),(β)+(β), and (γ)+(γ). Specifically, the maximum value is 50.6 GB, theintermediate value is 38.2 GB, and the minimum value is 25.8 GB.

In addition to conventional 50 GB, a 66 GB disc and a 100 GB disc aretargeted, and thus, a dual-stream disc such as that described above isalso implementable in terms of capacity.

Likewise, disc capacity required for a dual-stream disc on which arerecorded both a 4K_HDR stream compressed using HEVC and a 2K_SDR streamcompressed using HEVC is 88.9 GB based on the above-described (a)+(α),67.5 GB based on the above-described (b)+(β), 61.3 GB based on theabove-described (b)+(γ), and 57.3 GB based on the above-described(c)+(γ). Hence, such a dual-stream disc is implementable by a disc with100 GB capacity or a disc with 66 GB capacity.

[3-3. Details of the Types of Discs]

On a BD, more specifically, a video stream and a graphics stream (astream of graphics of the first exemplary embodiment) are recorded.Here, FIG. 24 is a diagram showing examples of a combination of a videostream and a graphics stream recorded on each disc for BDs includingdual-stream discs.

In FIG. 24, taking into account trouble of creating content (BD), agraphics stream is recorded at 2K resolution, regardless of a resolutionof a corresponding video stream. A graphics stream can be shared betweena 2K_SDR stream and a 4K_SDR stream. Note, however, that a graphicsstream is recorded in a luminance range that matches a luminance rangeof a corresponding video stream. When a video stream is HDR, an HDRgraphics stream is recorded. When a video stream is SDR, an SDR graphicsstream is recorded. Conversion of a graphics stream from SDR to HDR isperformed upon creation of content.

FIG. 25 is a diagram showing other examples of a combination of a videostream and a graphics stream recorded on each disc for BDs includingdual-stream discs.

In FIG. 25, taking into account trouble of creating content, a graphicsstream is recorded at 2K resolution and in an SDR luminance range,regardless of a resolution and a luminance range of a correspondingvideo stream. A graphics stream can be shared among all of a 2K_SDRstream, a 4K_SDR stream, a 2K_HDR stream, and a 4K_HDR stream. In thiscase, both conversion of a resolution of the graphics stream from 2K to4K and conversion of a luminance range of the graphics stream from SDRto HDR are performed by a Blu-ray device.

FIG. 26 is a diagram showing still other examples of a combination of avideo stream and a graphics stream recorded on each disc for BDsincluding dual-stream discs.

In FIG. 26, in order that a Blu-ray device does not need to performconversion of a graphics stream, upon creation of content, a graphicsstream is recorded such that a resolution and a luminance range of thegraphics stream match a resolution and a luminance range of acorresponding video stream.

[3-4. Processes of a Blu-Ray Device]

As described above, when there are a mix of various types of BDs anddisplay devices that support the BDs, a Blu-ray device needs to performprocesses such that a BD inserted into the Blu-ray device isappropriately displayed on a display device connected to the Blu-raydevice. The processes performed here include, for example, conversion ofa luminance range from HDR to SDR, up-conversion of a resolution from 2Kto 4K, and down-conversion of a resolution from 4K to 2K.

Then, when a new Blu-ray device capable of performing processes such asthose described above sends a video signal to a display device, theBlu-ray device needs to appropriately select an HDMI (registeredtrademark) standard and an HDCP standard. Specifically, the Blu-raydevice supports three sets of the HDMI/HDCP standards (HDMI 1.4/HDCP1.4, HDMI 2.0/HDCP 2.2, and HDMI 2.1/HDCP 2.2), and selects a version ofthe HDMI/HDCP standards to be used, according to a type of the displaydevice.

FIG. 27 is a schematic diagram showing content of processes performed bya Blu-ray device in a manner appropriate to various types of BDs andvarious types of display devices.

As shown in FIG. 27, Blu-ray device 300 selects each of a version ofHDMI and a version of HDCP, according to a type of a display deviceconnected to the Blu-ray device 300 (playback device). In addition,Blu-ray device 300 decodes an obtained video signal, encrypts thedecoded video signal using the HDCP of the selected version, and outputsthe encrypted video signal to the display device using the HDMI of theselected version.

Note that Blu-ray device 300 obtains a type of a display device, forexample, from the display device through an HDMI cable connectingBlu-ray device 300 to the display device. Alternatively, the type of thedisplay device may be included in display characteristics informationwhich is described in the first exemplary embodiment. In addition, auser may set display characteristics information in Blu-ray device 300by a manual operation. Note that, though not shown, Blu-ray device 300may include a first obtainer that obtains a type of a display device.

In addition, the type of the display device is, specifically, one of a2K_SDR-compatible TV, a 4K_SDR-compatible TV, a 2K_HDR-compatible TV,and a 4K_HDR-compatible TV. That is, the type of the display device isone of a first type indicating a display device whose resolution is theabove-described first resolution and which supports the above-describedfirst luminance range; a second type indicating a display device whoseresolution is the above-described second resolution and which supportsthe above-described first luminance range; a third type indicating adisplay device whose resolution is the above-described first resolutionand which supports the above-described second luminance range; and afourth type indicating a display device whose resolution is theabove-described second resolution and which supports the above-describedsecond luminance range.

For example, when a 2K_SDR-compatible TV is connected to Blu-ray device300, Blu-ray device 300 outputs a video signal using HDMI 1.4 and HDCP1.4. Specifically, Blu-ray device 300 encrypts a decoded video signalusing HDCP 1.4, and outputs the encrypted video signal to the2K_SDR-compatible TV using a communication protocol that supports HDMI1.4. Note that a communication protocol that supports HDMI 2.0 is, inother words, a communication protocol defined in HDMI 2.0.

At this time, when an inserted BD is a 4K_SDR-compatible BD,down-conversion of a resolution is required. When an inserted BD is a2K_HDR-compatible BD, conversion from HDR to SDR is required. When aninserted BD is a 4K_HDR-compatible BD, both down-conversion of aresolution and conversion from HDR to SDR are required.

Note that, when a 2K_SDR-compatible TV is connected to Blu-ray device300, pseudo-HDR conversion which is described in the first exemplaryembodiment may be performed.

For example, Blu-ray device 300 obtains a peak luminance of a displaydevice connected to Blu-ray device 300. When an obtained type of thedisplay device is the first type (2K_SDR-compatible TV) and the obtainedpeak luminance is higher than a peak luminance of the first luminancerange, Blu-ray device 300 converts a video signal to a luminance rangehaving the obtained peak luminance and then further converts the videosignal to the first luminance range. Then, Blu-ray device 300 encryptsthe converted video signal using HDCP 1.4, and outputs the encryptedvideo signal to the 2K_SDR-compatible TV using a communication protocolthat supports HDMI 1.4.

In addition, when a 4K_SDR-comptaible TV is connected to Blu-ray device300, Blu-ray device 300 outputs a video signal using HDMI 2.0 and HDCP2.2. Specifically, Blu-ray device 300 encrypts a decoded video signalusing HDCP 2.2, and outputs the encrypted video signal to the4K_SDR-compatible TV using a communication protocol that supports HDMI2.0.

At this time, when an inserted BD is a 2K_SDR-compatible BD,up-conversion of a resolution is required. When an inserted BD is a4K_HDR-compatible BD, conversion from HDR to SDR is required. When aninserted BD is a 2K_HDR-compatible BD, both up-conversion of aresolution and conversion from HDR to SDR are required.

Note that, when a 4K_SDR-compatible TV is connected to Blu-ray device300, pseudo-HDR conversion which is described in the first exemplaryembodiment may be performed.

For example, Blu-ray device 300 obtains a peak luminance of a displaydevice connected to Blu-ray device 300. When an obtained type of thedisplay device is the second type (4K_SDR-compatible TV) and theobtained peak luminance is higher than a peak luminance of the firstluminance range, Blu-ray device 300 converts a video signal to aluminance range having the obtained peak luminance and then furtherconverts the video signal to the first luminance range. Then, Blu-raydevice 300 encrypts the converted video signal using HDCP 2.2, andoutputs the encrypted video signal to the 4K_SDR-compatible TV using acommunication protocol that supports HDMI 2.0.

In addition, when a 2K_HDR-comptaible TV is connected to Blu-ray device300, Blu-ray device 300 outputs a video signal using HDMI 2.1 and HDCP2.2. Specifically, Blu-ray device 300 encrypts a decoded video signalusing HDCP 2.2, and outputs the encrypted video signal to the2K_HDR-compatible TV using a communication protocol that supports HDMI2.1.

At this time, when an inserted BD is a 4K_SDR-compatible BD and when aninserted BD is a 4K_HDR-compatible BD, down-conversion of a resolutionis required for both cases.

In addition, when a 4K_HDR-comptaible TV is connected to Blu-ray device300, the Blu-ray device 300 outputs a video signal using HDMI 2.1 andHDCP 2.2. Specifically, Blu-ray device 300 encrypts a decoded videosignal using HDCP 2.2, and outputs the encrypted video signal to the4K_HDR-compatible TV using a communication protocol that supports HDMI2.1.

At this time, when an inserted BD is a 2K_SDR-compatible BD and when aninserted BD is a 2K_HDR-compatible BD, up-conversion of a resolution isrequired for both cases.

[3-5. Details of Processes of the Blu-Ray Device]

Specific content of processes performed by Blu-ray device 300 accordingto a BD and a display device will be described below. Note thatprocessing examples described below are all processing examples for acase in which Blu-ray device 300 plays BDs where streams are recorded inthe combinations shown in FIG. 24.

3-5-1. Processing Example 1

FIG. 28 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a BD having a 2K_SDR stream recorded onthe BD.

As shown in FIG. 28, first, a video stream is played (decoded) by videodecoder 301, and a graphics stream is played (decoded) by graphicsdecoder 302.

Then, two pieces of data, i.e., the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, arecombined (blended) together by blender 303.

Then, the following processes are performed according to a displaydevice connected to Blu-ray device 300.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 transmits a 2K_SDR video signal obtained by thecombining performed by blender 303, to the 2K_SDR-compatible TV, usingHDMI 1.4 and HDCP 1.4.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 transmits a 2K_SDR video signal obtained by thecombining performed by blender 303, to the 2K_HDR-compatible TV, usingHDMI 2.1 and HDCP 2.2.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 up-converts, by 2K/4K converter 304, a 2K_SDR videosignal obtained by the combining performed by blender 303 to a 4K_SDRvideo signal, and transmits the converted 4K_SDR video signal to the4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 up-converts, by 2K/4K converter 304, a 2K_SDR videosignal obtained by the combining performed by blender 303 to a 4K_SDRvideo signal, and transmits the converted 4K_SDR video signal to the4K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

3-5-2. Processing Example 2

FIG. 29 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a BD having a 2K_HDR stream recorded onthe BD.

As shown in FIG. 29, first, a video stream is played (decoded) by videodecoder 301, and a graphics stream is played (decoded) by graphicsdecoder 302.

Then, two pieces of data, i.e., the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, arecombined together by blender 303.

Then, the following processes are performed according to a displaydevice connected to Blu-ray device 300.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 converts, by HDR/SDR converter 305, a 2K_HDR videosignal obtained by the combining performed by blender 303 to a 2K_SDRvideo signal, and transmits the converted 2K_SDR video signal to the2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 transmits a 2K_HDR video signal obtained by thecombining performed by blender 303, as it is to the 2K_HDR-compatibleTV, using HDMI 2.1 and HDCP 2.2.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 converts, by HDR/SDR converter 305, and up-converts,by 2K/4K converter 304, a 2K_HDR video signal obtained by the combiningperformed by blender 303 to a 4K_SDR video signal, and transmits theconverted 4K_SDR video signal to the 4K_SDR-compatible TV, using HDMI2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 up-converts, by 2K/4K converter 304, a 2K_HDR videosignal obtained by the combining performed by blender 303 to a 4K_HDRvideo signal, and transmits the converted 4K_HDR video signal to the4K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

3-5-3. Processing Example 3

FIG. 30 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a BD having a 4K_SDR stream (a 4K_SDRvideo stream and a 2K_SDR graphics stream) recorded on the BD.

As shown in FIG. 30, first, the video stream is decoded by video decoder301. On the other hand, the graphics stream is decoded by graphicsdecoder 302 and then up-converted by 2K/4K converter 306.

Then, two pieces of data, i.e., the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, arecombined together by blender 303.

Then, the following processes are performed according to a displaydevice connected to Blu-ray device 300.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 down-converts, by 4K/2K converter 307, a 4K_SDR videosignal obtained by the combining performed by blender 303 to a 2K_SDRvideo signal, and transmits the converted 2K_SDR video signal to the2K_SDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 down-converts, by 4K/2K converter 307, a 4K_SDR videosignal obtained by the combining performed by blender 303 to a 2K_SDRvideo signal, and transmits the converted 2K_SDR video signal to the2K_HDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 transmits a 4K_SDR video signal obtained by thecombining performed by blender 303, as it is to the 4K_SDR-compatibleTV, using HDMI 2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 transmits a 4K_SDR video signal obtained by thecombining performed by blender 303, as it is to the 4K_HDR-compatibleTV, using HDMI 2.1 and HDCP 2.2.

3-5-4. Processing Example 4

FIG. 31 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a BD having a 4K_HDR stream (a 4K_HDRvideo stream and a 2K_HDR graphics stream) recorded on the BD.

As shown in FIG. 31, first, the video stream is decoded by video decoder301. On the other hand, the graphics stream is decoded by graphicsdecoder 302 and then up-converted by 2K/4K converter 306.

Then, two pieces of data, i.e., the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, arecombined together by blender 303.

Then, the following processes are performed according to a displaydevice connected to Blu-ray device 300.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 converts a 4K_HDR video signal obtained by thecombining performed by blender 303 to a 2K_SDR video signal byconversion by HDR/SDR converter 305 and down-conversion by 4K/2Kconverter 307, and transmits the converted 2K_SDR video signal to the2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 down-converts, by 4K/2K converter 307, a 4K_HDR videosignal obtained by the combining performed by blender 303 to a 2K_HDRvideo signal, and transmits the converted 2K_HDR video signal to the2K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 converts a 4K_HDR video signal obtained by thecombining performed by blender 303 to a 2K_SDR video signal byperforming conversion by HDR/SDR converter 305, and transmits theconverted 2K_SDR video signal to the 4K_SDR-compatible TV, using HDMI2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 transmits a 4K_HDR video signal obtained by thecombining performed by blender 303, as it is to the 4K_HDR-compatibleTV, using HDMI 2.1 and HDCP 2.2.

3-5-5. Processing Example 5

FIG. 32 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a dual-stream disc having a 2K_HDR streamand a 2K_SDR stream recorded on the disc.

Blu-ray device 300 selects a stream to be extracted from the dual-streamdisc, according to a display device connected to Blu-ray device 300, andperforms processes such as those shown below.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 2K_SDR stream from the dual-stream disc.A video stream included in the extracted 2K_SDR stream is decoded byvideo decoder 301, and a graphics stream included in the extracted2K_SDR stream is decoded by graphics decoder 302. Blu-ray device 300combines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, andtransmits a 2K_SDR video signal obtained by the combining performed byblender 303 to the 2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 2K_HDR stream from the dual-stream disc.A video stream included in the extracted 2K_HDR stream is decoded byvideo decoder 301, and a graphics stream included in the extracted2K_HDR stream is decoded by graphics decoder 302. Blu-ray device 300combines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, andtransmits a 2K_HDR video signal obtained by the combining performed byblender 303 to the 2K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 2K_SDR stream from the dual-stream disc.A video stream included in the extracted 2K_SDR stream is decoded byvideo decoder 301, and a graphics stream included in the extracted2K_SDR stream is decoded by graphics decoder 302. Blu-ray device 300combines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, andup-converts, by 2K/4K converter 304, a 2K_SDR video signal obtained bythe combining performed by blender 303 and thereby generates a 4K_SDRvideo signal, and transmits the generated 4K_SDR video signal to the4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 2K_HDR stream from the dual-stream disc.A video stream included in the extracted 2K_HDR stream is decoded byvideo decoder 301, and a graphics stream included in the extracted2K_HDR stream is decoded by graphics decoder 302. Blu-ray device 300combines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, andup-converts, by 2K/4K converter 304, a 2K_HDR video signal obtained bythe combining performed by blender 303 and thereby generates a 4K_HDRvideo signal, and transmits the generated 4K_HDR video signal to the4K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

As described above, video decoder 301 and graphics decoder 302 functionas a second obtainer that selects one video signal from among aplurality of video signals according to a type of a display device, andobtains the selected video signal from a recording medium. The pluralityof video signals are for playing the same content recorded on thedual-stream disc (recording medium), and at least one of a resolutionand a luminance range differs between the plurality of video signals.

In addition, video decoder 301 and graphics decoder 302 function as adecoder that decodes the obtained video signal. Each of an HDMI 2.1/HDCP2.2 processing block, an HDMI 2.0/HDCP 2.2 processing block, and an HDMI1.4/HDCP 1.4 processing block in FIG. 32 functions as an output unitthat encrypts the decoded video signal using HDCP of a selected version,and outputs the encrypted video signal to the display device using HDMIof a selected version. The same also applies to the following processingexamples 6, 7, 10, and 11.

3-5-6. Processing Example 6

FIG. 33 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a dual-stream disc having a 4K_HDR streamand a 4K_SDR stream recorded on the disc. Note that the 4K_HDR streamused here includes a 4K_HDR video stream and a 2K_HDR graphics stream.The 4K_SDR stream includes a 4K_SDR video stream and a 2K_SDR graphicsstream.

Blu-ray device 300 selects a stream to be extracted from the dual-streamdisc, according to a display device connected to Blu-ray device 300, andperforms processes such as those shown below.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 4K_SDR stream from the dual-stream disc.The video stream included in the extracted 4K_SDR stream is decoded byvideo decoder 301. The graphics stream included in the extracted 4K_SDRstream is decoded by graphics decoder 302 and up-converted by 2K/4Kconverter 306. Blu-ray device 300 combines together, by blender 303, thevideo stream decoded by video decoder 301 and the graphics streamup-converted by 2K/4K converter 306, and down-converts, by 4K/2Kconverter 307, a 4K_SDR video signal obtained by the combining performedby blender 303. Blu-ray device 300 transmits a 2K_SDR video signalobtained by the down-conversion performed by 4K/2K converter 307 to the2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 4K_HDR stream from the dual-stream disc.The video stream included in the extracted 4K_HDR stream is decoded byvideo decoder 301. The graphics stream included in the extracted 4K_HDRstream is decoded by graphics decoder 302 and up-converted by 2K/4Kconverter 306. Blu-ray device 300 combines together, by blender 303, thevideo stream decoded by video decoder 301 and the graphics streamup-converted by 2K/4K converter 306, and down-converts, by 4K/2Kconverter 307, a 4K_HDR video signal obtained by the combining performedby blender 303. Blu-ray device 300 transmits a 2K_HDR video signalobtained by the down-conversion performed by 4K/2K converter 307 to the2K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 4K_SDR stream from the dual-stream disc.The video stream included in the extracted 4K_SDR stream is decoded byvideo decoder 301. The graphics stream included in the extracted 4K_SDRstream is decoded by graphics decoder 302 and up-converted by 2K/4Kconverter 306. Blu-ray device 300 combines together, by blender 303, thevideo stream decoded by video decoder 301 and the graphics streamup-converted by 2K/4K converter 306, and transmits a 4K_SDR video signalobtained by the combining performed by blender 303 to the4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 4K_HDR stream from the dual-stream disc.The video stream included in the extracted 4K_HDR stream is decoded byvideo decoder 301. The graphics stream included in the extracted 4K_HDRstream is decoded by graphics decoder 302 and up-converted by 2K/4Kconverter 306. Blu-ray device 300 combines together, by blender 303, thevideo stream decoded by video decoder 301 and the graphics streamup-converted by 2K/4K converter 306, and transmits a 4K_HDR video signalobtained by the combining performed by blender 303 to the4K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

3-5-7. Processing Example 7

FIG. 34 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 plays a dual-stream disc having a 4K_HDR streamand a 2K_SDR stream recorded on the disc. Note that the 4K_HDR streamused here includes a 4K_HDR video stream and a 2K_HDR graphics stream.The 2K_SDR stream includes a 2K_SDR video stream and a 2K_SDR graphicsstream.

Blu-ray device 300 selects a stream to be extracted from the dual-streamdisc, according to a display device connected to Blu-ray device 300, andperforms processes such as those shown below.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 2K_SDR stream from the dual-stream disc.The video stream included in the extracted 2K_SDR stream is decoded byvideo decoder 301, and the graphics stream included in the extracted2K_SDR stream is decoded by graphics decoder 302. Blu-ray device 300combines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, andtransmits a 2K_SDR video signal obtained by the combining performed byblender 303 to the 2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 2K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 4K_HDR stream from the dual-stream disc.The video stream included in the extracted 4K_HDR stream is decoded byvideo decoder 301. The graphics stream included in the extracted 4K_HDRstream is decoded by graphics decoder 302 and up-converted by 2K/4Kconverter 306. Blu-ray device 300 combines together, by blender 303, thevideo stream decoded by video decoder 301 and the graphics streamup-converted by 2K/4K converter 306, and down-converts, by 4K/2Kconverter 307, a 4K_HDR video signal obtained by the combining performedby blender 303. Blu-ray device 300 transmits a 2K_HDR video signalobtained by the down-conversion performed by 4K/2K converter 307 to the2K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

[3] When a 4K_SDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 2K_SDR stream from the dual-stream disc.The video stream included in the extracted 2K_SDR stream is decoded byvideo decoder 301, and the graphics stream included in the extracted2K_SDR stream is decoded by graphics decoder 302. Blu-ray device 300combines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, andup-converts, by 2K/4K converter 304, a 2K_SDR video signal obtained bythe combining performed by blender 303 and thereby generates a 4K_SDRvideo signal, and transmits the generated 4K_SDR video signal to the4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

[4] When a 4K_HDR-compatible TV is connected to Blu-ray device 300,Blu-ray device 300 extracts the 4K_HDR stream from the dual-stream disc.The video stream included in the extracted 4K_HDR stream is decoded byvideo decoder 301. The graphics stream included in the extracted 4K_HDRstream is decoded by graphics decoder 302 and up-converted by 2K/4Kconverter 306. Blu-ray device 300 combines together, by blender 303, thevideo stream decoded by video decoder 301 and the graphics streamup-converted by 2K/4K converter 306, and transmits a 4K_HDR video signalobtained by the combining performed by blender 303 to the4K_HDR-compatible TV, using HDMI 2.1 and HDCP 2.2.

In such processing example 7 and the above-described processing examples5 and 6, when a first video signal with the first luminance range and asecond video signal with the second luminance range are recorded on adual-stream disc (recording medium), if a luminance range supported by adisplay device is the first luminance range, Blu-ray device 300 selectsa video signal having the first luminance range, and if the luminancerange supported by the display device is the second luminance range,Blu-ray device 300 selects a video signal having the second luminancerange. By this, processes in Blu-ray device 300 are simplified.

3-5-8. Processing Example 8

A Blu-ray device may have a function of obtaining a peak luminance of adisplay device connected to the Blu-ray device, and performingpseudo-HDR conversion such as that described in the first exemplaryembodiment. In the following processing examples 8 to 11, content ofprocesses of Blu-ray 300 a added with such a function will be described.Note that Blu-ray device 300 a which is described in the followingprocessing examples 8 to 11 obtains a peak luminance of a displaydevice, for example, from the display device through an HDMI cableconnecting Blu-ray device 300 a to the display device. Alternatively,the peak luminance may be included in display characteristicsinformation which is described in the first exemplary embodiment.

FIG. 35 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 a having the pseudo-HDR conversion functionplays a BD having a 2K_HDR stream recorded on the BD. Note that contentof processes performed when a 2K_HDR-compatible TV is connected toBlu-ray device 300 a and content of processes performed when a4K_HDR-compatible TV is connected to Blu-ray device 300 a are the sameas the content of processes described in FIG. 29 and thus description ofthe content of processes is omitted.

When a 2K_SDR-compatible TV is connected to Blu-ray device 300 a andwhen a 4K_SDR-compatible TV is connected to Blu-ray device 300 a, a usercan view the same video as video of a conventional BD whose luminancesare represented by SDR, and can also enjoy HDR-like video having beenpseudo-HDR converted. In the following, content of processes for a caseof performing pseudo-HDR conversion will be described.

As shown in FIG. 35, first, a video stream is played (decoded) by videodecoder 301, and a graphics stream is played (decoded) by graphicsdecoder 302.

Then, two pieces of data, i.e., the decoded video stream and the decodedgraphics stream, are combined together by blender 303.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300 a,Blu-ray device 300 a determines, according to user's specification,whether to convert a 2K_HDR video signal obtained by the combiningperformed by blender 303 to a 2K_SDR video signal by HDR_SDR converter305, or to pseudo-HDR-convert the 2K_HDR video signal by pseudo-HDRconverter 308. Then, Blu-ray device 300 a transmits a 2K_SDR videosignal obtained by either one of the conversion performed by HDR/SDRconverter 305 and the conversion performed by pseudo-HDR converter 308to the 2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 4K_SDR-compatible TV is connected to Blu-ray device 300 a,Blu-ray device 300 a determines, according to user's specification,whether to convert a 2K_HDR video signal obtained by the combiningperformed by blender 303 to a 2K_SDR video signal by HDR_SDR converter305, or to pseudo-HDR-convert the 2K_HDR video signal by pseudo-HDRconverter 308. Then, Blu-ray device 300 a up-converts, by 2K/4Kconverter 304, a 2K_SDR video signal obtained by the conversion, andtransmits a 4K/SDR video signal obtained by the up-conversion performedby 2K/4K converter 304 to the 4K_SDR-compatible TV, using HDMI 2.0 andHDCP 2.2.

3-5-9. Processing Example 9

FIG. 36 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 a having the pseudo-HDR conversion functionplays a BD having a 4K_HDR stream (a 4K_HDR video stream and a 2K_HDRgraphics stream) recorded on the BD. Note that content of processesperformed when a 2K_HDR-compatible TV is connected to Blu-ray device 300a and content of processes performed when a 4K_HDR-compatible TV isconnected to Blu-ray device 300 a are the same as the content ofprocesses described in FIG. 31 and thus description of the content ofprocesses is omitted.

As shown in FIG. 36, first, the video stream is decoded by video decoder301. On the other hand, the graphics stream is decoded by graphicsdecoder 302 and then up-converted by 2K/4K converter 306.

Then, two pieces of data, i.e., the video stream decoded by videodecoder 301 and the graphics stream decoded by graphics decoder 302, arecombined together by blender 303.

[1] When a 2K_SDR-compatible TV is connected to Blu-ray device 300 a,Blu-ray device 300 a determines, according to user's specification,whether to convert a 4K_HDR video signal obtained by the combiningperformed by blender 303 to a 4K_SDR video signal by HDR_SDR converter305, or to pseudo-HDR-convert the 4K_HDR video signal by pseudo-HDRconverter 308. Then, Blu-ray device 300 a down-converts, by 4K/2Kconverter 307, a 4K_SDR video signal obtained by either one of theconversion performed by HDR/SDR converter 305 and the conversionperformed by pseudo-HDR converter 308, and transmits a 2K_SDR videosignal obtained by the down-conversion performed by 4K/2K converter 307to the 2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] When a 4K_SDR-compatible TV is connected to Blu-ray device 300 a,Blu-ray device 300 a determines, according to user's specification,whether to convert a 4K_HDR video signal obtained by the combiningperformed by blender 303 to a 4K_SDR video signal by HDR_SDR converter305, or to pseudo-HDR-convert the 4K_HDR video signal by pseudo-HDRconverter 308. Then, Blu-ray device 300 a transmits a 4K_SDR videosignal obtained by either one of the conversion performed by HDR/SDRconverter 305 and the conversion performed by pseudo-HDR converter 308to the 4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

3-5-10. Processing Example 10

FIG. 37 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 a having the pseudo-HDR conversion functionplays a dual-stream disc having a 2K_HDR stream and a 2K_SDR streamrecorded on the disc. Note that content of processes performed when a2K_HDR-compatible TV is connected to Blu-ray device 300 a and content ofprocesses performed when a 4K_HDR-compatible TV is connected to Blu-raydevice 300 a are the same as the content of processes described in FIG.32 and thus description of the content of processes is omitted.

[1] In a case in which a user makes a selection to obtain videoequivalent to video of a conventional BD whose luminances arerepresented by SDR when a 2K_SDR-compatible TV is connected to Blu-raydevice 300 a, Blu-ray device 300 a extracts the 2K_SDR stream from thedual-stream disc. A video stream included in the extracted 2K_SDR streamis decoded by video decoder 301, and a graphics stream included in theextracted 2K_SDR stream is decoded by graphics decoder 302. Blu-raydevice 300 a combines together, by blender 303, the video stream decodedby video decoder 301 and the graphics stream decoded by graphics decoder302, and transmits a 2K_SDR video signal obtained by the combiningperformed by blender 303 to the 2K_SDR-compatible TV, using HDMI 1.4 andHDCP 1.4.

On the other hand, in a case in which the user makes a selection toobtain HDR-like video when the 2K_SDR-compatible TV is connected toBlu-ray device 300 a, Blu-ray device 300 a extracts the 2K_HDR streamfrom the dual-stream disc. A video stream included in the extracted2K_HDR stream is decoded by video decoder 301, and a graphics streamincluded in the extracted 2K_HDR stream is decoded by graphics decoder302. Blu-ray device 300 a combines together, by blender 303, the videostream decoded by video decoder 301 and the graphics stream decoded bygraphics decoder 302, and pseudo-HDR-converts, by pseudo-HDR converter308, a 2K_HDR video signal obtained by the combining performed byblender 303. Then, Blu-ray device 300 a transmits a 2K_SDR video signalobtained by the pseudo-HDR conversion performed by pseudo-HDR converter308 to the 2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] In a case in which the user makes a selection to obtain videoequivalent to video of a conventional BD whose luminances arerepresented by SDR when a 4K_SDR-compatible TV is connected to Blu-raydevice 300 a, Blu-ray device 300 a extracts the 2K_SDR stream from thedual-stream disc. A video stream included in the extracted 2K_SDR streamis decoded by video decoder 301, and a graphics stream included in theextracted 2K_SDR stream is decoded by graphics decoder 302. Blu-raydevice 300 a combines together, by blender 303, the video stream decodedby video decoder 301 and the graphics stream decoded by graphics decoder302, up-converts, by 2K/4K converter 304, a 2K_SDR video signal obtainedby the combining performed by blender 303, and transmits a 4K_SDR videosignal obtained by the up-conversion performed by 2K/4K converter 304 tothe 4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

On the other hand, in a case in which the user makes a selection toobtain HDR-like video when the 4K_SDR-compatible TV is connected toBlu-ray device 300 a, Blu-ray device 300 a extracts the 2K_HDR streamfrom the dual-stream disc. A video stream included in the extracted2K_HDR stream is decoded by video decoder 301, and a graphics streamincluded in the extracted 2K_HDR stream is decoded by graphics decoder302. Blu-ray device 300 a combines together, by blender 303, the videostream decoded by video decoder 301 and the graphics stream decoded bygraphics decoder 302, and pseudo-HDR-converts, by pseudo-HDR converter308, a 2K_HDR video signal obtained by the combining performed byblender 303. Then, Blu-ray device 300 a up-converts, by 2K/4K converter304, a 2K_SDR video signal having been pseudo-HDR-converted bypseudo-HDR converter 308, and transmits a 4K_SDR video signal obtainedby the up-conversion performed by 2K/4K converter 304 to the4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

3-5-11. Processing Example 11

FIG. 38 is a diagram showing specific content of processes for a case inwhich Blu-ray device 300 a having the pseudo-HDR conversion functionplays a dual-stream disc having a 4K_HDR stream and a 2K_SDR streamrecorded on the disc. Note that the 4K_HDR stream used here includes a4K_HDR video stream and a 2K_HDR graphics stream. The 2K_SDR streamincludes a 2K_SDR video stream and a 2K_SDR graphics stream.

In addition, content of processes performed when a 2K_HDR-compatible TVis connected to Blu-ray device 300 a and content of processes performedwhen a 4K_HDR-compatible TV is connected to Blu-ray device 300 a are thesame as the content of processes described in FIG. 34 and thusdescription of the content of processes is omitted.

[1] In a case in which a user makes a selection to obtain videoequivalent to video of a conventional BD whose luminances arerepresented by SDR when a 2K_SDR-compatible TV is connected to Blu-raydevice 300 a, Blu-ray device 300 a extracts the 2K_SDR stream from thedual-stream disc. The video stream included in the extracted 2K_SDRstream is decoded by video decoder 301, and the graphics stream includedin the extracted 2K_SDR stream is decoded by graphics decoder 302.Blu-ray device 300 a combines together, by blender 303, the video streamdecoded by video decoder 301 and the graphics stream decoded by graphicsdecoder 302, and transmits a 2K_SDR video signal obtained by thecombining performed by blender 303 to the 2K_SDR-compatible TV, usingHDMI 1.4 and HDCP 1.4.

On the other hand, in a case in which the user makes a selection toobtain HDR-like video when the 2K_SDR-compatible TV is connected toBlu-ray device 300 a, Blu-ray device 300 a extracts the 4K_HDR streamfrom the dual-stream disc. The video stream included in the extracted4K_HDR stream is decoded by video decoder 301. The graphics streamincluded in the extracted 4K_HDR stream is decoded by graphics decoder302, and up-converted by 2K/4K converter 306. Blu-ray device 300 acombines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream up-converted by 2K/4K converter 306,pseudo-HDR-converts, by pseudo-HDR converter 308, a 4K_HDR video signalobtained by the combining performed by blender 303, and down-converts,by 4K/2K converter 307, the pseudo-HDR-converted video signal. Then,Blu-ray device 300 a transmits a 2K_SDR video signal obtained by thepseudo-HDR conversion performed by pseudo-HDR converter 308 and thedown-conversion performed by 4K/2K converter 307 to the2K_SDR-compatible TV, using HDMI 1.4 and HDCP 1.4.

[2] In a case in which the user makes a selection to obtain videoequivalent to video of a conventional BD whose luminances arerepresented by SDR when a 4K_SDR-compatible TV is connected to Blu-raydevice 300 a, Blu-ray device 300 a extracts the 2K_SDR stream from thedual-stream disc. The video stream included in the extracted 2K_SDRstream is decoded by video decoder 301, and the graphics stream includedin the extracted 2K_SDR stream is decoded by graphics decoder 302.Blu-ray device 300 a combines together, by blender 303, the video streamdecoded by video decoder 301 and the graphics stream decoded by graphicsdecoder 302, up-converts, by 2K/4K converter 304, a 2K_SDR video signalobtained by the combining performed by blender 303, and transmits a4K_SDR video signal obtained by the up-conversion performed by 2K/4Kconverter 304 to the 4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

On the other hand, in a case in which the user makes a selection toobtain HDR-like video when the 4K_SDR-compatible TV is connected toBlu-ray device 300 a, Blu-ray device 300 a extracts the 4K_HDR streamfrom the dual-stream disc. The video stream included in the extracted4K_HDR stream is decoded by video decoder 301. The graphics streamincluded in the extracted 4K_HDR stream is decoded by graphics decoder302, and up-converted by 2K/4K converter 306. Blu-ray device 300 acombines together, by blender 303, the video stream decoded by videodecoder 301 and the graphics stream up-converted by 2K/4K converter 306,and pseudo-HDR-converts, by pseudo-HDR converter 308, a 4K_HDR videosignal obtained by the combining performed by blender 303. Then, Blu-raydevice 300 a transmits a 4K_SDR video signal obtained by the pseudo-HDRconversion performed by pseudo-HDR converter 308 to the4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

[3-6. Details of Graphics Streams]

Supplemental remarks on graphics streams will be made below. FIG. 39 isa diagram showing detailed configurations of graphics streams.

An SDR graphics stream and an HDR graphics stream have the same basicspecifications of a graphics stream, but the HDR graphics stream hasconstraints such as Java (registered trademark; hereinafter, the same)color space (BT 2020 for 4K) and EOTF (EOTF for HDR). Hence, Javadrawing command 400 cannot be used as it is.

That is, a 4K_SDR-compatible BD, a 2K_HDR-compatible BD, and a4K_HDR-compatible BD need to inhibit Java drawing command 400.

Note that in specification of values of colors and luminances, byspecifying values that assume results of EOTF conversion (SDR->HDR),color space (BT709->BT2020) conversion, etc., it is also possible to useJava drawing command 400.

[3-7. Summary of the Third Exemplary Embodiment]

A Blu-ray device that plays a 4K-compatible BD or an HDR-compatible BDneeds to support four TVs: a 2K_SDR-compatible TV, a 2K_HDR-compatibleTV, a 4K_SDR-compatible TV, and a 4K_HDR-compatible TV. Specifically,the Blu-ray device needs to support three sets of HDMI/HDCP standards(HDMI 1.4/HDCP 1.4, HDMI 2.0/HDCP 2.2, and HDMI 2.1/HDCP 2.2).

Furthermore, when the Blu-ray device plays four types of Blu-ray discs(a 2K-SDR-compatible BD, a 2K_HDR-compatible BD, a 4K_SDR-compatible BD,and a 4K_HDR-compatible BD), the Blu-ray device needs to selectappropriate processes and HDMI/HDCP for each BD (content) and for eachdisplay device (TV) connected to the Blu-ray device. Furthermore, in acase of combining graphics with video, too, processes need to be changedaccording to a type of a BD and a type of a display device (TV)connected.

Due to this, internal processes of the Blu-ray device become verycomplicated. The above-described third exemplary embodiment providesvarious types of techniques for making the internal processes of theBlu-ray device relatively simple.

[1] When an HDR signal is displayed on a TV that does not support HDR,conversion from HDR to SDR is required. On the other hand, in theabove-described third exemplary embodiment, to allow a Blu-ray device tohave this conversion as an option, a configuration of a BD, called adual streams disc, is proposed.

[2] In addition, in the above-described third exemplary embodiment, anumber of types of combination of a video stream and a graphics streamis reduced by putting restrictions on graphics streams.

[3] In the above-described third exemplary embodiment, a number ofcombinations of complex processes in the Blu-ray device is significantlyreduced by the dual-stream disc and the restrictions on graphicsstreams.

[4] In the above-described third exemplary embodiment, internalprocesses and an HDMI process are presented that do not cause anycontradiction in a process of the dual-stream disc even when pseudo-HDRconversion is introduced.

Fourth Exemplary Embodiment

A fourth exemplary embodiment will be described below. Note thatdescription of the following fourth exemplary embodiment may overlapwith the description of the third exemplary embodiment. Note also thattechniques described in the following fourth exemplary embodiment may becombined with the techniques described in the third exemplaryembodiment.

[4-1. Summary]

FIG. 40 is a diagram showing types of BDs. As shown in FIG. 40, BDA(Blu-ray Disc Association) defines four types of BDs including threetypes of new BDs. A conventional BD is a 2K_SDR-compatible BD. The threetypes of new BDs are specifically a 4K_SDR-compatible BD, a2K_HDR-compatible BD, and a 4K_HDR-compatible BD. Note that the2K_SDR-compatible BD is a BD where a video signal whose resolution is 2K(first resolution) and whose luminance range is SDR (first luminancerange) is recorded as a stream (2K_SDR stream). The 4K_SDR-compatible BDis a BD where a video signal whose resolution is 4K (second resolution)and whose luminance range is SDR is recorded as a stream. The2K_HDR-compatible BD is a BD where a video signal whose resolution is 2Kand whose luminance range is HDR (second luminance range) is recorded asa stream. The 4K_HDR-compatible BD is a BD where a video signal whoseresolution is 4K and whose luminance range is HDR is recorded as astream.

By TV manufacturers providing HDR-compatible TVs (2K_HDR-compatible TVsand 4K_HDR-compatible TVs) in addition to current 2K_SDR-compatible TVsand 4K_SDR-compatible TVs, users can enjoy HDR image quality byoutputting an HDR video signal recorded on a new BD to an HDR-compatibleTV.

In order for the current 2K_SDR-compatible TV and 4K_SDR-compatible TVto display a video signal recorded on a new BD, there is a need toprovide a mechanism for converting (down-converting) the video signal(stream). FIGS. 41A and 41B are diagrams showing flows of video signalsfrom various types of BDs to various types of display devices.

FIG. 41A shows flows of video signals for a case in which new Blu-raydevice 500 a does not convert (down-convert) a video signal (stream).Current Blu-ray device 500 cannot play (decode) a new BD. In addition,when Blu-ray device 500 a plays a new BD and outputs a video signalwithout converting the video signal, a 4K_HDR-compatible TV can displayvideo of all of a 4K_HDR stream, a 2K_HDR stream, a 4K_SDR stream, and a2K_SDR stream. On the other hand, a 4K_SDR-compatible TV can displayvideo of the 4K_SDR stream and the 2K_SDR stream, but cannot displayvideo of the 4K_HDR stream and the 2K_HDR stream. In addition, a2K_SDR-compatible TV can display video of the 2K_SDR stream, but cannotdisplay video of the 4K_HDR stream, the 2K_HDR stream, and the 4K_SDRstream.

Hence, Blu-ray device 500 a requires conversion of a video signal. FIG.41B shows flows of video signals for a case in which Blu-ray device 500a converts a video signal. In a case of displaying video on the4K_SDR-compatible TV, Blu-ray device 500 a needs to convert a 4K_HDRstream recorded on a 4K_HDR-compatible BD to a 4K_SDR stream ((a) ofFIG. 41B). Likewise, in a case of displaying video on the4K_SDR-compatible TV, Blu-ray device 500 a needs to convert a 2K_HDRstream recorded on a 2K_HDR-compatible BD to a 2K_SDR stream ((b) ofFIG. 41B).

In addition, in a case of displaying video on the 2K_SDR-compatible TV,Blu-ray device 500 a needs to convert the 4K_HDR stream recorded on the4K_HDR-compatible BD to a 2K_SDR stream ((c) of FIG. 41B). Likewise, ina case of displaying video on the 2K_SDR-compatible TV, Blu-ray device500 a needs to convert the 2K_HDR stream recorded on the2K_HDR-compatible BD to a 2K_SDR stream ((b) of FIG. 41B). In addition,in a case of displaying video on the 2K_SDR-compatible TV, Blu-raydevice 500 a needs to convert a 4K_SDR stream stored on a4K_SDR-compatible BD to a 2K_SDR stream ((d) of FIG. 41B).

As described above, the new BD has three variations: a 4K_SDR-compatibleBD, a 2K_HDR-compatible BD, and a 4K_HDR-compatible BD. The new TV hasthree variations: a 4K_SDR-compatible TV, a 2K_HDR-compatible TV, and a4K_HDR-compatible TV.

The new BDs need to be protected by AACS (Advanced Access ContentSystem) 2.0 which is a new copyright protection technology for all BDs.In addition, when a video signal including an HDR signal (HDR metadata)is transmitted to the 4K_HDR-compatible TV, the video signal needs to betransmitted according to HDMI 2.0 and later standards. The HDMI 2.0 is anew content transmission technology. Furthermore, it is a general rulethat the video signal is protected by HDCP 2.x (e.g., HDCP 2.2) which isa copyright protection technology for a transmission channel used whencontent having a higher image quality than that of conventional content,such as HDR and 4K, is transmitted.

[4-2. Summary of Processes of a Playback Device]

As described above, to support display of various types of BDs on the2K_SDR-compatible TV and the 4K_SDR-compatible TV, conversion from HDRto SDR and down-conversion from 4K to 2K are required. In addition, HDMIand HDCP requirements also need to be satisfied. Hence, a playbackdevice (new Blu-ray device 500 a) performs the following processes. FIG.42 is a diagram for describing a summary of processes performed byBlu-ray device 500 a. (a) to (d) of FIG. 42 will be described below.

(a) Blu-ray device 500 a converts a 4K_HDR video signal (stream) to a4K_SDR video signal, and transmits the 4K_SDR video signal to a4K_SDR-compatible TV, using HDMI 2.0 and HDCP 2.2.

(b) Blu-ray device 500 a converts a 2K_HDR video signal to a 2K_SDRvideo signal, and transmits the 2K_SDR video signal to a2K_SDR-compatible TV or the 4K_SDR-compatible TV, using at least HDMI1.4 and HDCP 1.4.

(c) Blu-ray device 500 a converts a 4K_HDR video signal to a 4K_SDRvideo signal and down-converts the 4K_SDR video signal to a 2K_SDR videosignal. Blu-ray device 500 a transmits the 2K_SDR video signal to the2K_SDR-compatible TV, using at least HDMI 1.4 and HDCP 1.4.

(d) Blu-ray device 500 a converts a 4K_SDR video signal to a 2K_SDRvideo signal, and transmits the 2K_SDR video signal to the2K_SDR-compatible TV, using at least HDMI 1.4 and HDCP 1.4.

[4-3. First Playback Process]

Processes performed by a playback device (new Blu-ray device 500 a) toplay a BD and transmit a video signal to a TV will be described.

Content (BD) holds a standard digital output flag, and Blu-ray device500 a controls a playback process based on the standard digital outputflag. The standard digital output flag is an example of output controlinformation and an output flag.

FIG. 43 is a diagram showing a relationship between conversion performedby Blu-ray device 500 a and the standard digital output flag. Case (a)shown in FIG. 43 is a case of playing a BD where a 4K_HDR stream isrecorded, and Case (b) is a case of playing a BD where a 2K_HDR streamis recorded. Case (c) is a case of playing a BD where a 4K_SDR stream isrecorded.

In each of such cases, it is a general rule that a video signal isprotected by HDCP 2.x (hereinafter, described as HDCP 2.2, as anexample). In each of such cases, when a 4K_HDR-compatible TV thatsupports HDCP 2.2 is connected to Blu-ray device 500 a, there is no needto perform a conversion process when a video signal is output.

On the other hand, for a current 4K_SDR-compatible TV and a current 2KSDR-compatible TV that do not support HDCP 2.2, there is a need toconvert a video signal and output the converted video signal using, forexample, HDCP 1.4.

In order to thus allow output of the converted video signal using HDCP1.4 while protection using HDCP 2.2 is employed as a general rule, it isconsidered that AACS introduces a new standard digital output flag. Ineach case of FIG. 43, when the standard digital output flag of content(BD) indicates the flag “2”, Blu-ray device 500 a can support thecurrent 4K_SDR-compatible TV and the current 2K_SDR-compatible TV byperforming conversion which will be described below. That is, Blu-raydevice 500 a can output a converted video signal to the current4K_SDR-compatible TV and the current 2K_SDR-compatible TV, using HDCP1.4. Note that details of processes defined in the standard digitaloutput flag will be described later.

Here, in Case (a), when a connected TV is a current TV (the4K_SDR-compatible TV or the 2K_SDR-compatible TV), i.e., when conversionof a video signal is required, Blu-ray device 500 a performsdown-conversion and HDR-to-SDR conversion on a 4K_HDR stream stored on a4K_HDR-compatible BD.

In Case (b), when a connected TV is a current TV (the 4K_SDR-compatibleTV or the 2K_SDR-compatible TV), i.e., when conversion of a video signalis required, Blu-ray device 500 a performs HDR-to-SDR conversion on a2K_HDR stream stored on a 2K_HDR-compatible BD.

In Case (c), when a connected TV is a current TV (the 4K_SDR-compatibleTV or the 2K_SDR-compatible TV), i.e., when conversion of a video signalis required, Blu-ray device 500 a performs down-conversion on a 4K_SDRstream stored on a 4K_SDR-compatible BD.

Next, details of the standard digital output flag will be described.FIG. 44 is a diagram showing details of the standard digital outputflag. Note that values of the standard digital output flag (bitassignment) shown in FIG. 44 are an example.

In the standard digital output flag, the flag “0” indicates that“Related content can be output by technologies described in table D2. Toavoid confusion in the market, this value cannot be used until Dec. 31,2020.” Note that this date is an example. Likewise, the flag “1”indicates that “Related content can be output by both technologiesdescribed in table D1 and technologies described in table D2.” The flag“2” indicates that “If content is converted to a format that can beprotected by AACS 1.x, e.g., an SDR signal with a resolution of up toHD, then the content can be output by technologies described in tableD1. In addition to the above-described case, related content can beoutput by technologies described in table D2.”

Note that the flag “1” is an example of a first flag indicating thatoutput of content using a first copyright protection technology is notrestricted. The flag “2” is an example of a second flag indicating thatoutput of content using the first copyright protection technology isrestricted. The flag “0” is an example of a third flag indicating thatoutput of content using the first copyright protection technology is notallowed.

Here, the first copyright protection technology refers to one or morecopyright protection technologies defined in table D1, and a secondcopyright protection technology refers to one or more copyrightprotection technologies defined in table D2.

Table D1 and table D2 are two tables provided for standard digitaloutputs and enhanced digital outputs. By a transition from the standarddigital outputs to the enhanced digital outputs, copyright protectiontechnologies with further enhanced security are defined. FIG. 45 is adiagram showing table D1 specified in FIG. 44. FIG. 46 is a diagramshowing table D2 specified in FIG. 44.

Table D1 shown in FIG. 45 includes technologies such as DTCP, HDCP,WMDRM-ND, and PlayReady, as standard digital outputs authorized by AACS(AACS authorized standard digital outputs). Note that HDCP in FIG. 45refers to “HDCP 1.4”. On the other hand, table D2 shown in FIG. 46includes HDCP 2.2 and later and new technologies (entries) to be addedin the future by AACS review and approval, as enhanced digital outputs(AACS authorized enhanced digital outputs).

Note that table D1 is an example of a first table that defines one ormore copyright protection technologies included in the first copyrightprotection technology. Table D2 is an example of a second table thatdefines one or more copyright protection technologies included in thesecond copyright protection technology which is more enhanced than thefirst copyright protection technology. Table D1 and table D2 are storedin, for example, a storage unit (not shown) included in Blu-ray device500 a.

Content (BD) has a standard digital output flag such as that shown inFIG. 44, in usage rule or CCI (Copy Control Information). The standarddigital output flag can be selected by a content provider.

As described above, when a video signal obtained from a BD is a videosignal with 4K resolution or is a video signal with the HDR luminancerange, Blu-ray device 500 a performs processes such as those shownbelow.

Specifically, when the standard digital output flag is “1”, Blu-raydevice 500 a does not convert image quality of an obtained video signal,and outputs the video signal to a TV, using either one of the firstcopyright protection technology and the second copyright protectiontechnology which is determined according to an obtained type of thedisplay device.

In addition, when the standard digital output flag is “2”, Blu-raydevice 500 a converts a video signal to a 2K_SDR video signal, andoutputs the converted video signal to a TV, using the first copyrightprotection technology determined according to the obtained type of thedisplay device, or outputs a video signal to a TV using the secondcopyright protection technology.

In addition, when the standard digital output flag is “0”, Blu-raydevice 500 a outputs a video signal to a TV using the second copyrightprotection technology.

Furthermore, specifically, when the standard digital output flag is “1”in a case in which a TV does not support the second copyright protectiontechnology, Blu-ray device 500 a outputs a video signal to the TV usingthe first copyright protection technology.

In addition, when the standard digital output flag is “2” in a case inwhich a TV does not support the second copyright protection technology,Blu-ray device 500 a converts a video signal to reduce image quality,and outputs the video signal to the TV using the first copyrightprotection technology.

In addition, when the standard digital output flag is “0” in a case inwhich a TV does not support the second copyright protection technology,Blu-ray device 500 a inhibits output of a video signal.

[4-4. Second Playback Process]

Another example of processes performed by a playback device (new Blu-raydevice 500 a) to play a BD and transmit a video signal to a TV will bedescribed.

Content (BD) holds a standard digital output flag different than theabove-described one in FIG. 44, and Blu-ray device 500 a controls aplayback process based on the standard digital output flag.

FIG. 47 is a diagram showing a relationship between conversion performedby Blu-ray device 500 a and the standard digital output flag. Case (a)shown in FIG. 47 is a case of playing a BD where a 4K_HDR stream isrecorded, and Case (b) is a case of playing a BD where a 2K_HDR streamis recorded. Case (c) is a case of playing a BD where a 4K_SDR stream isrecorded.

In each of such cases, it is a general rule that a video signal isoutput, protected by HDCP 2.2. In each of such cases, when a4K_HDR-compatible TV that supports HDCP 2.2 is connected to Blu-raydevice 500 a, there is no need to perform a conversion process when avideo signal is output.

On the other hand, for a current 4K_SDR-compatible TV and a current2K_SDR-compatible TV that do not support HDCP 2.2, there is a need toconvert a video signal and output the converted video signal using, forexample, HDCP 1.4.

In order to thus allow output of the converted video signal using HDCP1.4 while protection using HDCP 2.2 is employed as a general rule, it isconsidered that AACS uses a standard digital output flag different thanthe above-described one in FIG. 44. In each case of FIG. 47, when thestandard digital output flag of content (BD) indicates the flag “0”,Blu-ray device 500 a can support the current 4K_SDR-compatible TV andthe current 2K_SDR-compatible TV by performing conversion which will bedescribed below. That is, Blu-ray device 500 a can output a convertedvideo signal to the current 4K_SDR-compatible TV and the current2K_SDR-compatible TV, using HDCP 1.4. Note that details of processesdefined in the standard digital output flag will be described later.

Here, in Case (a), when a connected TV is a current TV (the4K_SDR-compatible TV or the 2K_SDR-compatible TV), i.e., when conversionof a video signal is required, Blu-ray device 500 a performsdown-conversion and HDR-to-SDR conversion on a 4K_HDR stream stored on a4K_HDR-compatible BD.

In Case (b), when a connected TV is a current TV (the 4K_SDR-compatibleTV or the 2K_SDR-compatible TV), i.e., when conversion of a video signalis required, Blu-ray device 500 a performs HDR-to-SDR conversion on a2K_HDR stream stored on a 2K_HDR-compatible BD.

In Case (c), when a connected TV is a current TV (the 4K_SDR-compatibleTV or the 2K_SDR-compatible TV), i.e., when conversion of a video signalis required, Blu-ray device 500 a performs down-conversion on a 4K_SDRstream stored on a 4K_SDR-compatible BD.

FIG. 48 is a diagram showing details of the standard digital outputflag. Note that values of the standard digital output flag (bitassignment) shown in FIG. 48 are an example.

In the standard digital output flag, the flag “0” indicates that“Related content can be output by technologies described in table D2. Ifrelated content is converted to a format of an SDR signal with aresolution of up to HD (i.e., the content can be protected by AACS 1.x),then the converted content can be output by technologies described intable D1.” The flag “1” indicates that “Related content can be output byboth technologies described in table D1 and technologies described intable D2.”

Note that the flag “1” is an example of a first flag indicating thatoutput of content using a first copyright protection technology is notrestricted. The flag “0” is an example of a second flag indicating thatoutput of content using the first copyright protection technology isrestricted.

Here, the first copyright protection technology refers to one or morecopyright protection technologies defined in table D1, and a secondcopyright protection technology refers to one or more copyrightprotection technologies defined in table D2.

Note that table D1 used here is table D1 shown in FIG. 45, and table D2used here is table D2 shown in FIG. 46.

Content (BD) has a standard digital output flag such as that shown inFIG. 48, in usage rule or CCI (Copy Control Information). The standarddigital output flag can be selected by a content provider.

As described above, when a video signal obtained from a BD is a videosignal with 4K resolution or is a video signal with the HDR luminancerange, Blu-ray device 500 a performs processes such as those shownbelow.

Specifically, when the standard digital output flag is “1”, Blu-raydevice 500 a does not convert image quality of a video signal, andoutputs the video signal to a TV, using either one of the firstcopyright protection technology and the second copyright protectiontechnology.

In addition, when the standard digital output flag is “0”, Blu-raydevice 500 a converts a video signal to a 2K_SDR video signal, andoutputs the converted video signal to a TV, using the first copyrightprotection technology determined according to the obtained type of thedisplay device, or outputs a video signal to a TV using the secondcopyright protection technology determined according to theabove-described obtained type of the display device. The conversionperformed here is, for example, conversion to reduce a luminance rangeof the video signal.

More specifically, when the standard digital output flag is “1” in acase in which a TV does not support the second copyright protectiontechnology, Blu-ray device 500 a outputs a video signal to the TV usingthe first copyright protection technology determined according to theobtained type of the display device.

In addition, when the standard digital output flag is “0” in a case inwhich a TV does not support the second copyright protection technology,Blu-ray device 500 a converts a video signal to reduce image quality,and outputs the video signal to the above-described display device usingthe first copyright protection technology.

[4-5. Summary of the Fourth Exemplary Embodiment]

As described above, Blu-ray device 500 a obtains a type of a TVconnected to Blu-ray device 500 a, and obtains, from a BD, a videosignal of content recorded on the BD and a standard digital output flag.Here, the TV is an example of a display device and the BD is an exampleof a recording medium. In addition, the standard digital output flag isan example of output control information and is an example of an outputflag indicating rules about use of table D1 and table D2. The type of aTV includes at least information indicating whether the TV supports thefirst copyright protection technology. Such a type of a TV may beincluded in display characteristics information described in the firstexemplary embodiment.

Then, when the obtained standard digital output flag does not restrictoutput of content using the first copyright protection technology,Blu-ray device 500 a outputs the obtained video signal to the TV withoutconverting image quality of the video signal. When the obtained standarddigital output flag restricts output of content using the firstcopyright protection technology and output using the first copyrightprotection technology is performed according to the type of the TV,Blu-ray device 500 a converts the image quality of the obtained videosignal and outputs the video signal to the TV.

Specifically, Blu-ray device 500 a determines, according to the obtainedtype of a TV, whether to use the first copyright protection technologyor use the second copyright protection technology. When the video signalis output to the TV using the first copyright protection technology, thecopyright protection technologies defined in table D1 are used. When thevideo signal is output to the TV using the second copyright protectiontechnology, the copyright protection technologies defined in table D2are used.

Note that each operation of Blu-ray device 500 a such as that describedabove is specifically performed by each component included in Blu-raydevice 500 a. Blu-ray device 500 a may include, for example, a firstobtainer that obtains a type of a TV; a second obtainer that obtains astandard digital output flag; a third obtainer that obtains a videosignal; and an output unit that performs output control of the videosignal such as that described above.

Note that the third exemplary embodiment and the fourth exemplaryembodiment may be combined together. For example, when the standarddigital output flag restricts output of content using the firstcopyright protection technology in a case in which Blu-ray device 500 aplays a dual-stream disc, processes such as those shown in FIGS. 32 to34 and FIGS. 37 and 38 of the third exemplary embodiment may beperformed.

In this case, when Blu-ray device 500 a outputs a video signal to, forexample, a 2K_SDR-compatible TV, Blu-ray device 500 a uses the firstcopyright protection technology. In addition, when Blu-ray device 500 aoutputs a video signal to a 4K_SDR-compatible TV, a 2K_HDR-compatibleTV, and a 4K_HDR-compatible TV, Blu-ray device 500 a uses the secondcopyright protection technology.

(Overall Summary)

Although playback methods and playback devices according to one or aplurality of aspects of the present disclosure are described above basedon exemplary embodiments, the present disclosure is not limited to theexemplary embodiments. A mode where various modifications one skilled inthe art comes up with are made to the present exemplary embodiments, ora mode formed by combining together components of different exemplaryembodiments may also be included in a range of one or the plurality ofaspects of the present disclosure, without departing from the spirit andscope of the present disclosure.

For example, in each of the above-described exemplary embodiments, eachcomponent may be configured by dedicated hardware such as a circuit, ormay be implemented by executing a software program suitable for eachcomponent. Each component may be implemented by a program executor, suchas a CPU or a processor, reading and executing a software programrecorded in a recording medium, such as a hard disk or a semiconductormemory.

The present disclosure is useful as a playback method, a playbackdevice, and the like, that are capable of appropriately displaying videoon a display device.

What is claimed is:
 1. A playback method performed by a playback devicethat plays content, the playback method comprising: obtaining a type ofa display device connected to the playback device; obtaining, from arecording medium, output control information of the content recorded onthe recording medium; obtaining, from the recording medium, a videosignal of the content recorded on the recording medium; and outputtingthe obtained video signal to the display device; wherein the playbackdevice includes storage that stores: a first table defining one or morecopyright protection technologies included in a first copyrightprotection technology; and a second table defining one or more copyrightprotection technologies included in a second copyright protectiontechnology, the second copyright protection technology being moreenhanced than the first copyright protection technology, wherein in theobtaining of the output control information, an output flag indicatingrules about use of the first table and the second table is obtained, andwhether to use the first copyright protection technology or use thesecond copyright protection technology is determined, and wherein in theoutputting, when the obtained video signal is output to the displaydevice using the first copyright protection technology, the copyrightprotection technologies defined in the first table are used, and whenthe obtained video signal is output to the display device using thesecond copyright protection technology, the copyright protectiontechnologies defined in the second table are used.
 2. The playbackmethod according to claim 1, wherein the copyright protectiontechnologies defined in the first table include HDCP (High-bandwidthDigital Content Protection) 1.4, and wherein the copyright protectiontechnologies defined in the second table include HDCP 2.2. or a laterversion.
 3. The playback method according to claim 1, wherein theobtained video signal is a video signal with a second resolution havinga larger number of pixels than that of a first resolution, or a videosignal with a second luminance range including a first luminance rangeand having a higher peak luminance than that of the first luminancerange, and wherein in the outputting, (a) when the obtained output flagis a first flag indicating that output of content using the firstcopyright protection technology is not restricted, the obtained videosignal is output to the display device without converting the imagequality of the video signal, using either one of the first copyrightprotection technology and the second copyright protection technology,(b) when the obtained output flag is a second flag indicating thatoutput of content using the first copyright protection technology isrestricted, (i) the obtained video signal is converted to a video signalwith the first resolution and the first luminance range, and theconverted video signal is output to the display device using the firstcopyright protection technology, or (ii) the obtained video signal isoutput to the display device using the second copyright protectiontechnology, and (c) when the obtained output flag is a third flagindicating that output of content using the first copyright protectiontechnology is not allowed, the obtained video signal is output to thedisplay device using the second copyright protection technology.
 4. Theplayback method according to claim 3, wherein in the outputting, whenthe display device does not support the second copyright protectiontechnology, (a) when the obtained output flag is the first flag, theobtained video signal is output to the display device using the firstcopyright protection technology, (b) when the obtained output flag isthe second flag, the conversion is performed on the obtained videosignal to reduce the image quality, and the converted video signal isoutput to the display device using the first copyright protectiontechnology, and (c) when the obtained output flag is the third flag,output of the obtained video signal is inhibited.
 5. The playback methodaccording to claim 1, wherein the obtained video signal is a videosignal with a second resolution having a larger number of pixels thanthat of a first resolution, or a video signal with a second luminancerange including a first luminance range and having a higher peakluminance than that of the first luminance range, and wherein in theoutputting, (a) when the obtained output flag is a first flag indicatingthat output of content using the first copyright protection technologyis not restricted, the obtained video signal is output to the displaydevice without converting the image quality of the video signal, usingeither one of the first copyright protection technology and the secondcopyright protection technology, and (b) when the obtained output flagis a second flag indicating that output of content using the firstcopyright protection technology is restricted, (i) the obtained videosignal is converted to a video signal with the first resolution and thefirst luminance range, and the converted video signal is output to thedisplay device using the first copyright protection technology, or (ii)the obtained video signal is output to the display device using thesecond copyright protection technology.
 6. The playback method accordingto claim 5, wherein in the outputting, when the display device does notsupport the second copyright protection technology, (a) when theobtained output flag is the first flag, the obtained video signal isoutput to the display device using the first copyright protectiontechnology, and (b) when the obtained output flag is the second flag,the conversion is performed on the obtained video signal to reduce theimage quality, and the converted video signal is output to the displaydevice using the first copyright protection technology.
 7. A playbackdevice that plays content, the playback device comprising: circuitrythat, in operation, performs operations including: obtaining a type of adisplay device connected to the playback device; obtaining, from arecording medium, output control information of the content recorded onthe recording medium; obtaining, from the recording medium, a videosignal of the content recorded on the recording medium; and outputtingthe obtained video signal to the display device; and storage thatstores: a first table defining one or more copyright protectiontechnologies included in a first copyright protection technology; and asecond table defining one or more copyright protection technologiesincluded in a second copyright protection technology, the secondcopyright protection technology being more enhanced than the firstcopyright protection technology, wherein the circuitry, in operation,further performs operations including obtaining an output flagindicating rules about use of the first table and the second table, anddetermining whether to use the first copyright protection technology orto use the second copyright protection technology, and wherein, when theobtained video signal is output to the display device using the firstcopyright protection technology, the copyright protection technologiesdefined in the first table are used, and when the obtained video signalis output to the display device using the second copyright protectiontechnology, the copyright protection technologies defined in the secondtable are used.
 8. A playback device that plays content, the playbackdevice comprising: circuitry that, in operation, performs operationsincluding: obtaining a type of a display device connected to theplayback device; obtaining, from a recording medium, output controlinformation of the content recorded on the recording medium; obtaining,from the recording medium, a video signal of the content recorded on therecording medium; and outputting the obtained video signal to thedisplay device; and storage that stores: a first table defining one ormore copyright protection technologies included in the first copyrightprotection technology; and a second table defining one or more copyrightprotection technologies included in a second copyright protectiontechnology, the second copyright protection technology being moreenhanced than the first copyright protection technology, wherein thecircuitry, in operation, further performs operations including obtainingan output flag indicating rules about use of the first table and thesecond table, and determining whether to use the first copyrightprotection technology or to use the second copyright protectiontechnology, according to the obtained type of the display device,wherein the video signal obtained by the circuitry is a video signalwith a second resolution having a larger number of pixels than that of afirst resolution, or a video signal with a second luminance rangeincluding a first luminance range and having a higher peak luminancethan that of the first luminance range, and wherein the circuitry, inoperation, further performs operations including (a) outputting theobtained video signal to the display device without converting the imagequality of the video signal, using either one of the first copyrightprotection technology and the second copyright protection technology,when the obtained output flag is a first flag indicating that output ofcontent using the first copyright protection technology is notrestricted; and (b) (i) converting the obtained video signal to a videosignal with the first resolution and the first luminance range, andoutputting the converted video signal to the display device using thefirst copyright protection technology, or (ii) outputting the obtainedvideo signal to the display device using the second copyright protectiontechnology, when the obtained output flag is a second flag indicatingthat output of content using the first copyright protection technologyis restricted.